I am out of guesses on this one...you name it I tried it.
The machine shuts off just fine, but, select restart instead of shut down OR push the restart button the machine goes through the process of shutting down for a restart and gets to the black screen prior to the power back up and hangs up there. (no display, just black screen)
I thought it might be a problem in XP, and after fooling with all the hardware long enough, I wiped the drive, reinstalled XP and still experienced the problem.
If I disconnect the HDD before boot, and it goes to "no OS found" it will reset just fine with a push of the button. So, I can only assume it is relevant to XP somehow.
There is not a APM setting in the Power options
The only change in BIOS settings for Power Management is pretty much "Disable"
I swapped the power supply
I took every PCI card out and swapped the video card out with another
Swapped out both sticks of SDRAM
Disconnected CD Drive
Reset the BIOS to default
I have added no additional software to the fresh installed OS, tried with/without SP2 same result
What did I miss?
*** just a added note - same thing happens in safe mode