I do not know but try unistalling and reinstalling it usually asks to delete your saves for morrowind so i don't see why for oblivian. Just copy the saves you want and paste it somewhere else ex(it was in your program files, then make a folder in my documents and add the save there) You also need to say for this kind of help what the pop-up says so people have more understanding of the problem and they do not have to wait additional time to wait to respond so you might want to add what the pop up says now so people can help you faster. If it doesn't work after unistalling it(i advise to try it before too) see if in
local disk>program files>(it should be)bethesda softworks>now in here just go around in graphics or sthings and see if you find some obvious that is missing. Have you modded oblivian or not? that could be source of the problem. I'm not good with techie stuff but i can help people take the basic steps on what to do.
and do you know the basic steps of zombie protection? I do, learn them by heart they will be useful someday...
enjoy the instructions and remember learn them by heart....before the zombies remove it.