Thanks for the reply. Damn, that's a thread I wish I could email to myself 12 hours ago!
I'm not all that upset at having to wipe the drive, since everything is backed up. The problem is that I don't have anything that I can use to re-install Windows. I'll see if any of the info in that thread can help, if not I guess I'll just see about borrowing an external DVD drive.
ETA: I've actually done most of what was described in that thread, but without the benefit of an install DVD. I do have an installation DVD for my other computer that I could use to repair, if I got a new drive...