If there any unnecessary service that you should immediately disable, it's definitely the Indexing Service built into Windows XP. The purpose of this service is to search for files quickly. The Indexing service eats up CPU time, the more files you have the worse it gets. So lets free up some CPU time shall we?
The first thing we need to do is get into our Services. To do this we go to:
Start->Control Panel->Administrator Tools->Services
Then we find "Indexing Service" right click properties like show below:
If the service is started you can stop it. The we can disable it from starting up.
See how easy and simple that was?