With Windows 7, there are lots of services and processes that run in the background, providing support to other programs. By default, many are set to automatically run as soon as Windows starts up, meaning they’re continually using processor power and memory. However, you can change this setting to manual so a service will only start when Windows or another program actually needs it.
You also have the option to disable a service so that it never runs. This is best avoided unless you’re certain that you’ll never need it. Disabling a service that your computer needs can cause system errors.
Click Start. In the search box type 'services' and press Enter. Click Services from the results list.
In the Services window, right-click a service then select Properties. In the Startup type, set the service to Manual. Once done, you can close the window.