Computer board Q - Custom build powers up then shuts down quickly

I have researched this pretty throughly but, while a new MOBO is being contemplated, I wanted to see if anyone here had any insight to this.

Some details:
600w PSU, Cooler Master -- tested with multimeter -- fine.
Biostar TForce P965 -- the suspected problem.

So if i just have the 24pin plugged in the system boots, but there is no video output. If I plug the additional ATX 12V 4 Pin in, I get this issue of power up then immediate shutdown. It's not:
(1) RAM
(2) Video card itself
(3) CPU
(4) PSU
(5) A short due to the board touching the case.

I've deduced a couple of things -- the video cards power is controlled by this ATX 12V 4 Pin connector, and the ATX 12V 4 Pin connector itself is shorted or damaged.

All research seems to suggest that this has happened to people on multiple mother boards, all of which seem to be socket 775. This motherboard has been run everyday all day for the past 6 years or so. Socket 775 is discontinued at this point, but this computer ran like a champ. Unfortunately, I can't find the exact board anywhere, which would be my preference.

Anyone think there is any other possibly workaround here? It's a relatively cheap fix since socket 775 mobo's look like they are going for 30-60 bucks. I'm probably going to do a new build in about 1-2 years.