Whenever you make a change in your system there is always a possibility that something could go wrong. Therefore, you'll want to have a way to return your system to its previous state whenever necessary.
The way to do this is with "System Restore".
Whenever you start your computer, the core operating system for Windows (Windows XP or Windows Vista) will load into your computer,
However, there is also a host of programs and services that also start. Many of these are necessary for your computer to operate correctly. However, many of them are for features that you may not use at all.
You can reduce the number of programs and services that start on boot-up.
The fewer programs and services that run, the more quickly Windows will boot and the more smoothly and faster your computer can process information.