Windows XP/2000 - [Resolved] XP running very slow posted in the Operating Systems forums; My BIOS doesn't have "default settings", it has "Fail-Safe" and "Optimized" settings. Tried them both, it didn't change anything...
Got it back from a shop, it's all working fine now. Turned out to be a software problem, corrupt windows files, drivers missing, and having 2 anti-virus programs running at once.