Bootup Hanging at Mup.sys

For some reason my system keeps hanging when booting up on the windows splash screen, then when i try to start it in safe mode it hang on .../System32/Drivers/mup.sys .

The problem started when i switched the case of the computer due to the power button beeing fauty. There has been no update of hardware apart from the case.

I have already tied the following:
Clean install of XP
Clean install on a new Hard Disk
Disabling the mup driver (this made it hang in the same place but did not disable the driver)
Checked all the connections and ran the computer with just the basic components

now i do not know what to do, anyone know the best way to fix this problem

Thank you for the advice, iv just been through and checked everything is connected properly annd seated properly within the case, no change. I have also tryed it with the case fas disconnected incase there was a problem with power getting to all the components, no change either. Does anyone know what the next driver to be loaded is after Mup.sys or any other alternative suggestion?