Sounds like you might have ruined your Windows instalation completely.
If you have all your important data backed up, and you think you are ready to loose everything on your hard drive, then I recommend that you completely redo everything.
(Reformat it, loosing all your data, documents, music, etc)
Why?
If you go ahead trying to install Windows XP again, you are going to get one heck of a funky installation. (Like my Windows 98 SE 1/2)
This will result in a few errors, and possibly slowed performance.
If you must keep the installation, would you mind telling us exactly what the disk usage status on all your drives are?
When you "left the disk in and let it install another windows", did you do a repair install? Or a complete install?