When you say "in DOS", do you mean you booted up using a DOS recovery disk, or do you mean you were using the command line cmd? If it was the former, then I would say that you have a bad video card and it needs to be replaced.
Otherwise, I would recommend going to Alienware for drivers, not nVIDIA, as some manufacturers modify the drivers slightly to better suit their custom hardware.
http://support.alienware.com/Support_Pages/Restricted_Pages/driver_downloads.aspxWhile you're at it, you should update all the drivers in the system.
--Nick