Good Point,, some good info here too,,,
On the Hardware Advisor,, it has to run with an OS on it,,, so,, would you be able to install 98 version on it? run the advisor, and will let you know if XP is compliant.,.
On the MOBO issue,, there is a good point,, is the MOBO ACPI compliant,, that info you would need to find in the MOBO manual,, or with a BIOS upgrade that may be posted at the MOBO manufacturer's site...
I still believe that you have a hardware issue here,,,
cheers,