If there is one bloated and unnecessary service that you should immediately disable, it’s definitely the Indexing Service built into Windows XP. The idea behind it is that you can search for files more quickly if it is enabled, however if you do not have more files in the computer, it is fine if you disabled the service.
The indexing service seems to eat up a lot of CPU on every machine, especially when you have more files, it could definitely make the system slow.