Only two weeks ago, I'd done a full backup, thanks to the wonders of a speedy external hard drive. The data loss wasn't that bad. The only irreplaceable email I could remember, I'd printed off yesterday. The only irreplaceable file was a game one; I could live without it. Would I spend all of Friday reinstalling my system software? Could I rescue the additional data? Was my hard drive well-and-truly dead? The sentimentalist in me would miss all those graduation-related emails.
But I woke, to a friendly household of houseguests, irisbleu and lifegivingsword, and to a computer that complacently booted up as if nothing had happend the night before. Just in case, I'm going to back up again.
Edited a few minutes later from another machine: I spoke too soon. Same problem. If I can get it to reboot normally again, the first thing I'm doing is data salvage, not wishful thinking computer use. Still. Same data loss applies: not too bad.
Later still: No real progress. I backed up one file I cared about, then the OS hung again. Next time, if there is one, I go straight to the external hard drive for backups, not do it the slow way on the USB drive. I actually was using some form of logic when I started with the USB drive - my drive's less likely to overheat when using it due to slower access speeds, and faulty fan is a problem my laptop may have. But I'm just guessing. Until I can keep it up long enough to back up and then do diagnostics, I won't be able to tell.
Mid-afternoon: The machine is safely backed up, passed all the hardware tests, and has had a pram reset. It's been up and stable for fiftten minutes now. Will it last? Who knows. If I knew what had gone wrong in the first place, I would be more certain.
The next day: Based on its stability so far, I'm fairly certain my laptop is back in full working order. The problem was a loose RAM card - the intermittent connection caused the freezing.