If you arrived here from a search engine and have not seen the previous parts to this tutorial please start by reading Part 1 of how to disable windows vista services.
Application Management: The Application Management service relys heavily on Group Policy. If you do not use Group Policy, which users of Vista Home Basic and Home Premium won’t because it isn’t available you can safely disable it. If you work in a networked enviornment you will need this service and your IT guys won’t let you disable it. The optimal setting is DISABLED and the safe setting is MANUAL.
Background Intelligent Transfer Service: BITS is basically a download manager that allows for downloads to be resumed later. It is mainly used for windows updates. It will resume downloads after you log back on to the system. If you would like to speed up the boot process on your system I would advise that you change the default time from 3AM to a time your system is normally on otherwise the service will check for updates when you turn the system on. The optimal setting is MANUAL and the safe setting is AUTOMATIC.
Base Filtering Engine: If you are using a hardware firewall such as a router and you don’t use VPN tunneling or Internet connection sharing it is safe to turn it off. Turning it off will result in a less secure computer because the windows firewall and IPsec rely on it. The optimal setting is DISABLED and the safe setting is AUTOMATIC.
Block Level Backup Engine Service: This is the engine that performs block level backup and recovery of data. Mainly used by the Windows backup application. The optimal setting is DISABLED and the safe setting is MANUAL.
Certificate Propagation: This service is used for the handling of Smart Card certificates. What are Smart Cards used for? One use would be instead of using a password to login to Windows Vista you would use a smart card. Smart Cards look similar to a credit card. The optimal setting is DISABLED and the safe setting is MANUAL.
CNG Key Isolation: This service is required by wireless networks. For example if you own a laptop and are on a wireless network leave this setting on the default values, otherwise you could turn off your wireless adapter. The optimal setting is DISABLED only if you are not using a wireless network. The safe setting is AUTOMATIC.
COM+ Event System: This service is dependant of other services. If you run Visual Studio applications like myself, I would advise leaving it at the default values. The optimal setting is AUTOMATIC and the safe setting is AUTOMATIC.
COM+ System Application: If the service is stopped, most COM+-based components will not function properly. The optimal setting is DISABLED and the safe setting is MANUAL.
Computer Browser: You do not need this service if you are not in a network enviornment. I really don’t think you need it at all to be honest as long as one computer on the network has it enabled, even then it is doubtful. Basically all it does is maintain a list of computers on the network and supply that list to systems that are designated as browsers. The optimal setting is DISABLED and the safe setting is MANUAL.
Cryptographic Services: This is a Catalog Database Service, it confirms the signatures of Windows files and allows new programs to be installed. Also manages Root Certificates, etc. Windows Update will automatically set this to manual if it is needed. The optimal setting is MANUAL and the safe setting is AUTOMATIC.
DCOM Server Process Launcher: Provides launch functionality for DCOM services. Almost every service relies on it. You can’t disable it even if you wanted to. The optimal setting is AUTOMATIC and the safe setting is AUTOMATIC.
Desktop Window Manager Session Manager: This service provides a portion of the new Windows Themes and reverts back to basic setting styles when it runs applications that are not compatible with Vista Aero. In a nutshell it provides desktop window manager startup and maintenance services. This is one of the heavier background services in Vista, it consistantly uses CPU power. The optimal setting is DISABLED but you will loose all the fancy and pretty AERO stuff. The safe setting is AUTOMATIC.
DFS Replication: The DFS Replication service is used to keep files synchronized across computers on a network. Can be used on local or wide area networks. The service uses a protocol called (RDC) Remote Differential Compression, meaning only the files that have been changed since the last replication will be updated. The optimal setting is DISABLED and the safe setting is MANUAL.
Continue on to part 3 of how to disable windows vista services.