Oblivion Game & Patch Problems

I've read this whol forum and followed everyones directions on what I should do. But when I tried to install the patch it gave me this error. "Old File not found. However, a file of the same name was found. No updates done since file contents do not match." I'm still getting the same error message when I try to play Oblivion "Oblivion has encounterd a problem and needs to close." I have all the requirements to play this game so I don't get why it's still giving me errors.