Essexboy is on many Forums and expert…he will respond.
In mean time some reading:
http://www.aitechsolutions.net/mupdotsysXPhang.html
http://www.aitechsolutions.net/winxpnoboot.html
http://answers.microsoft.com/en-us/windows/forum/windows_xp-system/mupsys-error-on-windows-xp-pro/b1483aab-cc1c-4ab5-b7de-9a5ae9a10a40
http://www.bleepingcomputer.com/forums/t/393442/windows-xp-freezes-at-mupsys-in-safe-modeno-administrator-passowrd/
…but don’t try anything until he answers and gives advice on best next-steps…
…I’m sure he will ask…do you have a XP Windows O/S CD/DVD ?..in other words access to this CD/DVD for Repair Console ?