I'd try and track down a copy of XP so you can boot from the CD and get to the recovery console. From there you might be able to get chkdsk /f to help you out.
If that doesn't work, time to break out your study manuals - you may need to manually edit your boot.ini file. This can be a bit tricky if you haven't done it before. I can't imagine how it got hosed but the error you're getting is exactly what happens when your boot.ini points to a drive that isn't there. In any case, you need to access your boot.ini file and make sure it's pointing XP to the drives and partition where your system files are. Again, this isn't easy and you'll need to do a little research to get the correct syntax. It's not rocket science but it's not intuitive either. One more thing to consider - if you've formatted with NTFS you're going to need to come up with a tricky way to access that file because you can't just use a vanilla boot disk - you'll need a new version of NTFDOS or something to get around the file security.
In short, you're going to save yourself a huge headache if you can find an XP CD and boot to the recovery console.
Good luck.
Huz
