OK, OP checking in here. Just want to let y'all know that I've been running fine on my new old Windows 7 machine for more than a month now, with no real problems. I guess you just have to half beat to death first, then it lies down and starts behaving.
Actually, I have a crackpot theory why it's working well. I took (someone's, forget exactly who) advice and installed that backup program, dism, and started making backup images. Since doing that I've had no problems. My theory is that the threat of having a valid backup has scared the gremlins away, and they haven't bothered me since.
I even found a kinda-sorta solution to that fuzzy-text problem I was having. I put in a call to SetProcessDPIAware() to make my code "high-DPI aware" (tried it in my editor). Well, it works, with some issues. The text is, overall, much clearer, though there are still weird artifacts seen depending on which font one uses. The main problem was with the text in the RichEdit control, which was definitely fuzzy or blurry. Now it's sharper, but there are still strange things, like the top or bottom line of the equal sign disappearing. (The best font I found for monospaced text is something called "Monospac821 BT", which I think came from an old Corel disc I had from a couple decades ago.)
The other thing is that right after calling that function, the size of everything in the program changed! But I found that just choosing a new font for the edit control pretty much fixed that. I still have no idea how this whole "DPI-aware" thing works.
No blue screens. The only crashes are from running the programs I write, which is to be expected. (Not really crashes, just the program dies. No big deal.)
Regarding the text issue: I am still completely mystified why it is that I have so much trouble with some software (like my own programs, or older software for Win2000 or XP), but absolutely no problems with, say, Opera: everything in my browser windows is rendered perfectly. Clear and sharp. By the way, I've had no other issues at all with Opera, which makes those reports I read about it in this thread somewhat baffling. I did have that certificate issue after reinstalling W7, but after applying that patch that someone here posted everything's been fine.
Like I say, you just have to wave a torch in the face of those gremlins, scare them off ...