How do I switch off computer programs?

[Louise07]

I've heard that various programs automatically start up when a computer is switched on, but that the programs can be 'switched off' to make the computer run quicker. How do I do this? TIA

[Ethel]

A programme called start up inspector is free and does exactly what you want.

And it's easy to change back if you want to.

http://www.windowsstartup.com/startupinspector .php

[Phantaxus]

You can also turn off some services.

see
http://www.optimizingpc.com/optimize/windowsse rvices.html