Aaaaaccchhh

Firefox has reset itself to some sort of minimalistic version—all the preferences have reset themselves, though oddly the bookmarks and extensions are still there, and, exceedingly annoyingly, the search bar has no engines to choose from, and when I go to the add engines page it doesn't work. I've already tried uninstalling it and reinstalling it, and using System Restore. Nothing brings them back.

I would install Firefox 2, which I haven't bothered to do yet, but what if I do, and the search engines are still AWOL?