Here is a partial list of services in Windows 7, along with their descriptions:
ActiveX Installer (AxInstSV)
Provides User Account Control validation for the installation of ActiveX controls from the Internet and enables management of ActiveX control installation based on Group Policy settings. This service is started on demand and if disabled the installation of ActiveX controls will behave according to default browser settings.
Application Experience
Processes application compatibility cache requests for applications as they are launched
Application Identity
Determines and verifies the identity of an application. Disabling this service will prevent AppLocker from being enforced.
Application Layer Gateway Service
Provides support for 3rd party protocol plug-ins for Internet Connection Sharing
Background Intelligent Transfer Service
Transfers files in the background using idle network bandwidth. If the service is disabled, then any applications that depend on BITS, such as Windows Update or MSN Explorer, will be unable to automatically download programs and other information.
BitLocker Drive Encryption Service
BDESVC hosts the BitLocker Drive Encryption service. BitLocker Drive Encryption provides secure startup for the operating system, as well as full volume encryption for OS, fixed or removable volumes. This service allows BitLocker to prompt users for various actions related to their volumes when mounted, and unlocks volumes automatically without user interaction. Additionally, it stores recovery information to Active Directory, if available, and, if necessary, ensures the most recent recovery certificates are used. Stopping or disabling the service would prevent users from leveraging this functionality.
Bluetooth Support Service
The Bluetooth service supports discovery and association of remote Bluetooth devices. Stopping or disabling this service may cause already installed Bluetooth devices to fail to operate properly and prevent new devices from being discovered or associated.
Certificate Propagation
Copies user certificates and root certificates from smart cards into the current user’s certificate store, detects when a smart card is inserted into a smart card reader, and, if needed, installs the smart card Plug and Play minidriver.
COM+ Event System
Supports System Event Notification Service (SENS), which provides automatic distribution of events to subscribing Component Object Model (COM) components. If the service is stopped, SENS will close and will not be able to provide logon and logoff notifications. If this service is disabled, any services that explicitly depend on it will fail to start.
Computer Browser
Maintains an updated list of computers on the network and supplies this list to computers designated as browsers. If this service is stopped, this list will not be updated or maintained. If this service is disabled, any services that explicitly depend on it will fail to start.
Cryptographic Services
Provides four management services: Catalog Database Service, which confirms the signatures of Windows files and allows new programs to be installed; Protected Root Service, which adds and removes Trusted Root Certification Authority certificates from this computer; Automatic Root Certificate Update Service, which retrieves root certificates from Windows Update and enable scenarios such as SSL; and Key Service, which helps enroll this computer for certificates. If this service is stopped, these management services will not function properly. If this service is disabled, any services that explicitly depend on it will fail to start.
Desktop Window Manager Session Manager
Provides Desktop Window Manager startup and maintenance services
Diagnostic Policy Service
The Diagnostic Policy Service enables problem detection, troubleshooting and resolution for Windows components. If this service is stopped, diagnostics will no longer function.
Diagnostic System Host
The Diagnostic System Host is used by the Diagnostic Policy Service to host diagnostics that need to run in a Local System context. If this service is stopped, any diagnostics that depend on it will no longer function.
Distributed Link Tracking Client
Maintains links between NTFS files within a computer or across computers in a network.
DNS Client
The DNS Client service (dnscache) caches Domain Name System (DNS) names and registers the full computer name for this computer. If the service is stopped, DNS names will continue to be resolved. However, the results of DNS name queries will not be cached and the computer’s name will not be registered. If the service is disabled, any services that explicitly depend on it will fail to start.
Extensible Authentication Protocol
The Extensible Authentication Protocol (EAP) service provides network authentication in such scenarios as 802.1x wired and wireless, VPN, and Network Access Protection (NAP). EAP also provides application programming interfaces (APIs) that are used by network access clients, including wireless and VPN clients, during the authentication process. If you disable this service, this computer is prevented from accessing networks that require EAP authentication.
Function Discovery Provider Host
The FDPHOST service hosts the Function Discovery (FD) network discovery providers. These FD providers supply network discovery services for the Simple Services Discovery Protocol (SSDP) and Web Services – Discovery (WS-D) protocol. Stopping or disabling the FDPHOST service will disable network discovery for these protocols when using FD. When this service is unavailable, network services using FD and relying on these discovery protocols will be unable to find network devices or resources.
Group Policy Client
The service is responsible for applying settings configured by administrators for the computer and users through the Group Policy component. If the service is stopped or disabled, the settings will not be applied and applications and components will not be manageable through Group Policy. Any components or applications that depend on the Group Policy component might not be functional if the service is stopped or disabled.
HomeGroup Listener
Makes local computer changes associated with configuration and maintenance of the homegroup-joined computer. If this service is stopped or disabled, your computer will not work properly in a homegroup and your homegroup might not work properly. It is recommended that you keep this service running.
Human Interface Device Access
Enables generic input access to Human Interface Devices (HID), which activates and maintains the use of predefined hot buttons on keyboards, remote controls, and other multimedia devices. If this service is stopped, hot buttons controlled by this service will no longer function. If this service is disabled, any services that explicitly depend on it will fail to start.
IKE and AuthIP IPsec Keying Modules
The IKEEXT service hosts the Internet Key Exchange (IKE) and Authenticated Internet Protocol (AuthIP) keying modules. These keying modules are used for authentication and key exchange in Internet Protocol security (IPsec). Stopping or disabling the IKEEXT service will disable IKE and AuthIP key exchange with peer computers. IPsec is typically configured to use IKE or AuthIP; therefore, stopping or disabling the IKEEXT service might result in an IPsec failure and might compromise the security of the system. It is strongly recommended that you have the IKEEXT service running.
Internet Connection Sharing (ICS)
Provides network address translation, addressing, name resolution and/or intrusion prevention services for a home or small office network.
IP Helper
Provides tunnel connectivity using IPv6 transition technologies (6to4, ISATAP, Port Proxy, and Teredo), and IP-HTTPS. If this service is stopped, the computer will not have the enhanced connectivity benefits that these technologies offer.
KtmRm for Distributed Transaction Coordinator
Coordinates transactions between the Distributed Transaction Coordinator (MSDTC) and the Kernel Transaction Manager (KTM). If it is not needed, it is recommended that this service remain stopped. If it is needed, both MSDTC and KTM will start this service automatically. If this service is disabled, any MSDTC transaction interacting with a Kernel Resource Manager will fail and any services that explicitly depend on it will fail to start.
Media Center Extender Service
Allows Media Center Extenders to locate and connect to the computer.
Microsoft iSCSI Initiator Service
Manages Internet SCSI (iSCSI) sessions from this computer to remote iSCSI target devices. If this service is stopped, this computer will not be able to login or access iSCSI targets. If this service is disabled, any services that explicitly depend on it will fail to start.
Multimedia Class Scheduler
Enables relative prioritization of work based on system-wide task priorities. This is intended mainly for multimedia applications. If this service is stopped, individual tasks resort to their default priority.
Netlogon
Maintains a secure channel between this computer and the domain controller for authenticating users and services. If this service is stopped, the computer may not authenticate users and services and the domain controller cannot register DNS records. If this service is disabled, any services that explicitly depend on it will fail to start.
Network Connections
Manages objects in the Network and Dial-Up Connections folder, in which you can view both local area network and remote connections.
Network Location Awareness
Collects and stores configuration information for the network and notifies programs when this information is modified. If this service is stopped, configuration information might be unavailable. If this service is disabled, any services that explicitly depend on it will fail to start.
Offline Files
The Offline Files service performs maintenance activities on the Offline Files cache, responds to user logon and logoff events, implements the internals of the public API, and dispatches interesting events to those interested in Offline Files activities and changes in cache state.
Peer Name Resolution Protocol
Enables serverless peer name resolution over the Internet using the Peer Name Resolution Protocol (PNRP). If disabled, some peer-to-peer and collaborative applications, such as Remote Assistance, may not function.
Peer Networking Identity Manager
Provides identity services for the Peer Name Resolution Protocol (PNRP) and Peer-to-Peer Grouping services. If disabled, the Peer Name Resolution Protocol (PNRP) and Peer-to-Peer Grouping services may not function, and some applications, such as HomeGroup and Remote Assistance, may not function correctly.
Plug and Play
Enables a computer to recognize and adapt to hardware changes with little or no user input. Stopping or disabling this service will result in system instability.
PNRP Machine Name Publication Service
This service publishes a machine name using the Peer Name Resolution Protocol. Configuration is managed via the netsh context ‘p2p pnrp peer’
Power
Manages power policy and power policy notification delivery.
Problem Reports and Solutions Control Panel Support
This service provides support for viewing, sending and deletion of system-level problem reports for the Problem Reports and Solutions control panel.
Protected Storage
Provides protected storage for sensitive data, such as passwords, to prevent access by unauthorized services, processes, or users.
Remote Access Auto Connection Manager
Creates a connection to a remote network whenever a program references a remote DNS or NetBIOS name or address.
Remote Desktop Configuration
Remote Desktop Configuration service (RDCS) is responsible for all Remote Desktop Services and Remote Desktop related configuration and session maintenance activities that require SYSTEM context. These include per-session temporary folders, RD themes, and RD certificates.
Remote Desktop Services UserMode Port Redirector
Allows the redirection of Printers/Drives/Ports for RDP connections
Remote Procedure Call (RPC) Locator
In Windows 2003 and earlier versions of Windows, the Remote Procedure Call (RPC) Locator service manages the RPC name service database. In Windows Vista and later versions of Windows, this service does not provide any functionality and is present for application compatibility.
Routing and Remote Access
Offers routing services to businesses in local area and wide area network environments.
Secondary Logon
Enables starting processes under alternate credentials. If this service is stopped, this type of logon access will be unavailable. If this service is disabled, any services that explicitly depend on it will fail to start.
Security Accounts Manager
The startup of this service signals other services that the Security Accounts Manager (SAM) is ready to accept requests. Disabling this service will prevent other services in the system from being notified when the SAM is ready, which may in turn cause those services to fail to start correctly. This service should not be disabled.
Server
Supports file, print, and named-pipe sharing over the network for this computer. If this service is stopped, these functions will be unavailable. If this service is disabled, any services that explicitly depend on it will fail to start.
Simple TCP/IP Services
Supports the following TCP/IP services: Character Generator, Daytime, Discard, Echo, and Quote of the Day.
Smart Card Removal Policy
Allows the system to be configured to lock the user desktop upon smart card removal.
SNMP Trap
Receives trap messages generated by local or remote Simple Network Management Protocol (SNMP) agents and forwards the messages to SNMP management programs running on this computer. If this service is stopped, SNMP-based programs on this computer will not receive SNMP trap messages. If this service is disabled, any services that explicitly depend on it will fail to start.
SPP Notification Service
Provides Software Licensing activation and notification
Storage Service
Enforces group policy for storage devices
System Event Notification Service
Monitors system events and notifies subscribers to COM+ Event System of these events.
Task Scheduler
Enables a user to configure and schedule automated tasks on this computer. The service also hosts multiple Windows system-critical tasks. If this service is stopped or disabled, these tasks will not be run at their scheduled times. If this service is disabled, any services that explicitly depend on it will fail to start.
Telephony
Provides Telephony API (TAPI) support for programs that control telephony devices on the local computer and, through the LAN, on servers that are also running the service.
Thread Ordering Server
Provides ordered execution for a group of threads within a specific period of time.
UPnP Device Host
Allows UPnP devices to be hosted on this computer. If this service is stopped, any hosted UPnP devices will stop functioning and no additional hosted devices can be added. If this service is disabled, any services that explicitly depend on it will fail to start.
Virtual Disk
Provides management services for disks, volumes, file systems, and storage arrays.
Web Management Service
The Web Management Service enables remote and delegated management capabilities for administrators to manage for the Web server, sites and applications present on this machine.
Windows Audio
Manages audio for Windows-based programs. If this service is stopped, audio devices and effects will not function properly. If this service is disabled, any services that explicitly depend on it will fail to start
Windows Backup
Provides Windows Backup and Restore capabilities.
Windows CardSpace
Securely enables the creation, management, and disclosure of digital identities.
Windows Connect Now – Config Registrar
WCNCSVC hosts the Windows Connect Now Configuration which is Microsoft’s Implementation of Wi-Fi Protected Setup (WPS) protocol. This is used to configure Wireless LAN settings for an Access Point (AP) or a Wi-Fi Device. The service is started programmatically as needed.
Windows Driver Foundation – User-mode Driver Framework
Manages user-mode driver host processes.
Windows Event Collector
This service manages persistent subscriptions to events from remote sources that support WS-Management protocol. This includes Windows Vista event logs, hardware and IPMI-enabled event sources. The service stores forwarded events in a local Event Log. If this service is stopped or disabled event subscriptions cannot be created and forwarded events cannot be accepted.
Windows Firewall
Windows Firewall helps protect your computer by preventing unauthorized users from gaining access to your computer through the Internet or a network.
Windows Image Acquisition (WIA)
Provides image acquisition services for scanners and cameras
Windows Management Instrumentation
Provides a common interface and object model to access management information about operating system, devices, applications and services. If this service is stopped, most Windows-based software will not function properly. If this service is disabled, any services that explicitly depend on it will fail to start.
Windows Media Center Scheduler Service
Starts and stops recording of TV programs within Windows Media Center
Windows Modules Installer
Enables installation, modification, and removal of Windows updates and optional components. If this service is disabled, install or uninstall of Windows updates might fail for this computer.
Windows Process Activation Service
The Windows Process Activation Service (WAS) provides process activation, resource management and health management services for message-activated applications.
Windows Time
Maintains date and time synchronization on all clients and servers in the network. If this service is stopped, date and time synchronization will be unavailable. If this service is disabled, any services that explicitly depend on it will fail to start.
WinHTTP Web Proxy Auto-Discovery Service
WinHTTP implements the client HTTP stack and provides developers with a Win32 API and COM Automation component for sending HTTP requests and receiving responses. In addition, WinHTTP provides support for auto-discovering a proxy configuration via its implementation of the Web Proxy Auto-Discovery (WPAD) protocol.
WLAN AutoConfig
The WLANSVC service provides the logic required to configure, discover, connect to, and disconnect from a wireless local area network (WLAN) as defined by IEEE 802.11 standards. It also contains the logic to turn your computer into a software access point so that other devices or computers can connect to your computer wirelessly using a WLAN adapter that can support this. Stopping or disabling the WLANSVC service will make all WLAN adapters on your computer inaccessible from the Windows networking UI. It is strongly recommended that you have the WLANSVC service running if your computer has a WLAN adapter.
Workstation
Creates and maintains client network connections to remote servers using the SMB protocol. If this service is stopped, these connections will be unavailable. If this service is disabled, any services that explicitly depend on it will fail to start.
WWAN AutoConfig
This service manages mobile broadband (GSM & CDMA) data card/embedded module adapters and connections by auto-configuring the networks. It is strongly recommended that this service be kept running for best user experience of mobile broadband devices.