Blue Screen of Death

Check this out, I just installed service pack six on a NT 4.0 machine and all was fine and dandy. Until I went to the “start menu–>Run” and typed in any command with a front slash. As soon as I hit the front slash that awful blue screen reared itsugly head at me. So I tried to unistall service pack six, but some how it is tied into internet explorer and I can’t add/remove the program period. How do I remove sp6 so I can install sp4?!