Typing "Services" in the Search box under the Start Menu will open the tool with exactly this name. Essentially, the utility will provide an exhaustive list of all the processes in Windows Vista complete with name, description, status and startup type. The console will allow you to stop, restart or start various services across the operating system, as well as getting an insight into all the properties of the services enumerated by the tool.

Services that do not affect the user experience in any way. You should not even notice a difference when using these settings, but it is possible. Disables unnecessary services. Many heavy and most likely unused services have been disabled. This is much lighter than 'Safe'. Aero disabled, but Themes left alone, as many people will blindly run this without reading what services are gone, and will be surprised/angry to see themes disappear.

All services that are not necessary to every day use and windows update have been disabled. Themes is disabled, Aero is disabled, firewall disabled. This assumes you have your OWN firewall/AV software installed!