Hi. I just read the end of your other thread.
When you installed/powered up on the new PSU, there was no need to set/reset anything in the BIOS setup?
Even fitting a new/different CPU doesn't require any "setting up" as it is normally done automatically by the initial boot sequence when the BIOS checks all connected hardware.
Maybe you have "de-tuned" something by manually configuring...try going into the setup, reset Defaults, save and exit. See what happens. At best, this is your starting point for hardware fault finding. It sounds to me like there is a mobo driver problem(s) by incorrect fault reporting, so you could try a System Restore or even a complete System File Check, but I am not sure how you go about these with Win2k.