Windows will not load normally or in safe mode?

I have a Dell Dimension Desktop with Windows XP Media Edition..I had to restart the computer due to cable modem with internet and it starts out loading fine but when it gets to the black screen with the Windows logo and the blue line underneath that runs back and forth it just stalls and never continues on to finish booting. I tried to restart and load in safe mode but it stalls at System32\Drivers\Mup.sys I do not have the CD to try and repair the problem (it was stolen)...Is there ANYTHING that can possibly be done to save my computer?? I have very precious pictures that I just transferred off my laptop onto there out of fear my laptop was crashing and I have yet to get them backed up to cd =( Please Please Please help me...any and all help is greatly appreciated =)