OK. So here's the deal.

I found the hardware button on my computer that initiates the Nuke From Orbit function: it also explained the hitherto unexplained D:/ partition on the hard drive—it was in fact the Windows System Install disk, cleverly disguised as a partition.  (So does this make it a Windows Install Disk...drive?)

The data's safely backed up elsewhere—recent newsbreak: IT'S ABOUT 30 DVDS OF DATA.  The nuke button was pressed—

You don't normally associate pictures of grass glittery with dewdrops with the button that basically says "Hi, I see your computer's totally fucked.  You want me to fix that?"  Seeing as I was going to have to wipe anyway, I decided to see if the onboard system wipe would work.

*two hours later, and a LOT of Windows Updating*

It seems to have worked.  The majority of the functionality is back, but I don't have a lot of my programs.  And the ones that I do have aren't behaving like I'm used to them doing.  I figure, I'll run the updater tools until a quarter to one, and then go to sleep, take care of it later.

…Improvement, yes.  But still tedious work.  So cue the Tosca. (Which isn't even on my computer right now, thanks to that nuke.)