Strange shutdown/reboot issue?

[Lateuk]

Hello,
My PC has developed a problem and for the life of me i cannot figure out what is wrong.

The symptoms are after a clean install of XP i find when i go to shutdown or restart, the computer goes through the motions but never actually does the final bit to power off or restart.

I am posting here because i believe it is a hardware issue as even during the install of XP the installer is not able to reboot its self.

But to add confusion to the mix my dual booted copy of Vista will reboot the computer and restart the computer fine?!?

The problem is i have moved a few cables and fans and removed a sound card from my setup as well as reinstalling XP so it is really hard to conclusivly decide what is at fault.

Any ideas?

 

[Lateuk]

Thanks for the help so far.

I am now starting to agree that it is an ACPI issue, so i have tried flashing my BIOS and also forcing windows XP install (using the F5 method) to install the ACPI Multiprocessor HAL.

This has still not fixed the problem as the windows XP installer still cannot restart the computer during install so i assume it will not be able to once fully installed.

For some reason it seams XP will not recognise i have an ACPI motherboard, but it did originally when i installed XP a few years ago! MAkes no sense.