Grab a second harddrive and reinstall windows back onto the new drive then install the second one as a slave. After you have windows setup just drag and drop the files. That's what I would do, if it is more than just messed up partion table, you might have more problems than you orginally thought. Plus I would run a full virus/spyware check just to make sure.
Edit: Just realized that I suggested what you didn't want to do. Next time I'll read more carefully. Here is a program that before it went to shareware it could remake partions and other nifty things on the fly.
http://www.prime-expert.com/ebcd/index.php EBCD.