hmm, a couple things to try and a couple questions.
1, do you have any mods, official or unofficial, installed (especially ones that play with graphics)?
2, when you reinstalled oblivion did you do a full uninstall then delete all the remaining files just to be sure? (particularly the ini files)
3, do you have the latest patchs?
4, can you think of anything driver related that you've installed between it working and it not working? btw, a restore point won't neccesarily help if you have a driver file corrupted. its not replacing all the files with old versions, just doing some registry tinkering.
try the oblivion unofficial patch, it fixes ALOT of bugs, whether this is one of them i dunno, but its worth a try.
link:
http://www.tesnexus.com/downloads/file.php?id=5296
try reinstalling directx (thats directx related error i think), also try several video card drivers, maybe the current version you have doesnt like oblivion.