Run disk clean up then Degrag.
Run disk defrag 5~7 times in a row, until it completes in c.10 seconds. XP's degrag doesn't do much in one go so running it a few times gets better results (this was fixed in Win7, dunno about Vista though)
Ah, I thought disk clean up was defrag, I'm running on norwegian sys and the translations aren't always so good. Anyway, lots of good suggestions here, I'll try em and see what works!
edit: this disc defrag is taking long as hell, I guess that means there is alot of crap to clean up? ;P it's been on for quite a while now, and it's not even 1/5th of the way