Of course, I'd figure it out now, immediately after posting about it. I remembered how I fixed it last time! Imageshack Quickshot (a utility that takes screenshots and uploads them to Imageshack.us automatically) has issues on this machine and does that to whatever keys it's shortcuts are bound to.
Well, I have an InterestIng IssUe. my I and U keys only work wIth shIft held. It appears to be a software problem, sInce It's stlll I and U If I swItch keyboard layoUts (I normally Use Dvorak). I seem to remember that thIs has happened before, bUt I don't remember the solUtIon.
Keyboard IssUe (lIkely software)