Gate GT4022 Power issue

[kenmha]

I have a computer that's acting very bizarre! In fact, its so odd, I have not experienced anything like this in all of the years I've been dealing with PC's. It's a Gateway GT4022 (AMD 64 4000+). It boots up just fine, but during any OS installation the computer shut itself off. I used memtest86 and SeaTools to test the RAM and HDD; they both passed with flying colors. I thought maybe it was a heat issue, so I applied a new layer of AS5 to no avail. Would a bad cpu causes a pc to power down during installation? I also swapped out the PSU and it did the same thing.

Windows 7 Installation: After the "Windows is loading file bar disappear, starting Windows is shown briefly; then powers off.

Windows XP Installation: Setup is copying files usually gets to 70-75% then powers off.

Ubuntu Installtion: Does not shut off, but the screen goes all black. Even with a PCI-E video card.

 

[popatim]

Check out the capacitors ont he motherboard, they could be going bad. Youcan find examples at badcaps dot net in the bottom right of the screen. They should be flat across the top and no signs of any leaks at the bottom.

 

[kenmha]

I visually inspected all of the capacitors and they look fine. The computer works find during memtest (using both UBCD and HBCD). Is it possible that a BIOS virus is prohibiting the installation of an OS? I checked Gateway website and there's not one single BIOS update.