Windows XP keeps a record of all files on the hard disk so when you do a search on the hard drive it is faster. There is a downside to this and because the computer has to index all files, it will slow down normal file commands like open, close, etc.
If you do not do a whole lot of searches on your hard drive then I suggest turnning this feature off:
1. Control Panel
2. Administrative Tools
4. Disable Indexing Services