In trying to start up in safe mode my computer list a number of file directories and freezes on . . . system 32\drivers\mup.sys

Can anyone tell what is wrong and how do I fix it?

Thanks

Hi,

Mainly not starting in safe mode is resulted of either corrupted windows (you will need to reinstall or repair windows), or virus attack were some viruses will prevent you from going into safe mode.

There is a very good chance that you have been hit by a malicious software that as part of its actions to protect itself disable Safe Mode. What version of XP are you running? Sp number?