I just upgraded to XP this weekend, and did a clean install. Got to the screen about another windows installation, just go ahead and go over it. Also, I would format your hard drive as NTFS (don't choose the quick one, or convert, just do a full). I got a lot of better response out of it. One thing that really improved the performance is putting more memory in - absolutely critical that you do this, and now is the time - RAM is soooooo cheap (I got 256M for $30). Go to
www.crucial.com for the best prices, and free two day shipping.
Thanks. Regarding the NTFS, I read somewhere that you should wait to make sure your XP is running properly and then convert since that file format isn't compatible with other OSs.