This is a compilation of descriptions of almost all Windows 7 and Windows 8 Services as given in Windows Services Properties:
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.
Monitors ambient light sensors to detect changes in ambient light and adjust the display brightness. If this service is stopped or disabled, the display brightness will not adapt to lighting conditions.
Processes application compatibility cache requests for applications as they are launched