I have been upgraded to Windows 10, and everything was working fine yesterday. I was able to use all my usual applications, and shut down for the night.
This morning, when I went to start my computer, it cycled the startup a few times, and then gave me a completely illegible blue screen - if you've ever played with the horizontal hold on an old TV, this is how illegible it was. Literally no coherently connected pixels, so I have no error message to work from. I did a restore back to 11/26 9PM (which was when it was freshly updated and working fine), but no dice. I was finally able to get functional with Safe Mode plus Networking. All drivers appear to be up-to-date according to my Device Manager. (Although, I am suspecting it's still an issue with my Display Driver from the symptoms.)
EDIT: Okay - it seems to be behaving now. But could someone tell me why reinstalling my printer driver would correct a problem that caused such a massive display glitch?