You could try recovering MUP.sys from the windows XP recovery console. To do this

Insert the Windows XP Home Edition/Professional/Media Center Recovery disk that came with your system.
Reboot your computer-> Press F12 Rapidly -> when the Boot Menu loads, choose "Boot From CD-ROM." When all files in the Disk are loaded, choose "R" for Repair.

I have 2 versions of windows now installed
1) Nothing on it but it runs (C:/RECOVER)
2) My old one with everything it but it BSOD's (C:/WINDOWS)

Can I just go on the working one then goto C:/WINDOWS/System32/Drivers/Mup.sys and just delete it? I'll try that now I guess. I thought Mup.sys was a needed file though.

I took out Mup.sys and now it just crashed on the driver before that...can someone please help me I don't know how to fix this and after google-ing for a long time I only found that 1) It could be a pirted copy of windows...but I got it from Dell so that couldn't be the problem or
2)Hardware error, but I can run the second version of windows I installed, C:/RECOVER works just fine...
Does any have any ideas please?