Numerous display issues, unsure how to diagnose the problem

That is good news. You can try re-installing your existing drivers in the regular Windows mode... unless the installer tells you to do otherwise. Look around for the option to do a clean install. That should remove the old drivers and any settings.

If re-installing fails, hunt down an older version of the drivers and try them.

Turns out, the problems just went away temporarily.

You might try booting to a Ubuntu or Linux Mint DVD and surf from there for several hours to see if the issue shows up.