Problem restarting dell xps 400?

I am told that if I go through a process using the opperating disk that I could save my files and fix the computer but it would cost $200 for dell to help me. Does anyone else know how? I have tried rebooting in safe mode and the previous date settings but previouS date settings leave the black loading screen and the safe leaves me on a page that stops while loading partition\window\system32\drivers\mup.sy…