After a bit of googling, I realized that there was an entry in the boot.ini file still referring to the old install, so on bootup the computer was letting me select. I just opened it up in notepad, deleted the line that referenced the old install, and it was all good.
Also, there were a few system files that were being absolutely stubborn about being deleted, despite the fact that they were definitely not in use, so I had to download a few random utilities to clean up the last shreds of the old install.
It still bugs me that the windows folder is called C:\Windows.0, and my user default user profile folder is User.0, but I'm not anal retentive enough to try and find a way to get all the folders renamed correctly (would likely involve a shit-ton of rejiggering settings). Enough to be bothered by it, but not enough to fix it... lol