I might as well update. I've downloaded and burned a copy of Hiren's Boot CD just in case, and I've backed up all my important stuff (some of my games, pictures, music, porn) onto my external drive.
One thing, though. Microsoft Security Essentials thought that the extracted files for Hiren (the stuff you're supposed to make an image of) were malware. Is MSE on to something, or is it just paranoid?