I can't think of a reason that it would do any harm but that doesn't necessarily mean it won't...
Back to things not showing up, I assume you've already run virus/spy-ware checks so I'd suggest you try the repair function on the XP disc.
Alternatively there are some other fixes you could try here
but, personally, I think the repair function is your best bet.
Do you know how to do that?
@TK Trooper - it can be caused by malware, registry corruption, hard drive faults, all sorts..