Guess what it actually was. That's right, a total waste of time. Except for gorging myself on tasty Olive Garden. That part was okay.
When I got to the store they made me wait in line for like 15 mintues to get another copy of the receipt, after which I gave them a bunch of other addresses and phone numbers and such, at which point they finally told me it would be two weeks before I would hear anything back about anything at all. No quick-check diagnostic? I ask. Anything at all to see what is actually the problem? No, they say, of course not, because we can't even boot it up. I bet, they say, it's a hard drive failure. (Nevermind I tried booting off a Knoppix CD, which totally doesn't work now, whereas once upon a time it did)
Thanks but no thanks; I might as well send it to Sony where it only takes a week.
The most tragic thing is while at Olive Garden I briefly got it to boot up, but had no network to shunt my precious recent data off to (although the vast majority of the stuff I have is backed up) Now that I've gotten back to campus (after having to take the 67A, EBA, and 61A in sequence, because of the 67A's fucked up late-night saturday route that goes to Wilkinsburg instead of Oakland) of course it is dead again.