Nvidia 9600GT OC problem

I recently received a Nvidia 9600GT OC from BMG as a replacement card for my 7950GT OC which had broke, After I installed the card bios wouldn't boot and I was left with full power to my case and drives etc but no power to my keyboard, mouse (lights) or monitor, so I tried putting in an old pci-e card I had been using and had same problem, I presumed it was a lose wire somewhere at the time and fiddled around with it till it eventually came on and I swapped the cards again putting the 9600 back in.

Now about a week later I have the same problem again BIOS won't boot. After about 5 hours of swapping cables it has just came back on and Im posting on it now, but what could be causing this?

I have tried resetting BIOS, even flashed it to newest version.

Swapped out everything one by one drives, ram, to no effect. Even removed all my ram at one point to see would I get any beeps from bios and I got none.
All the wires were secured properly to made sure of that.

Any help would be great!

Specs:

Hardware:

CPU: AMD Athlon 4200+ X2
MotherBoard: Asus M2N-SLi Deluxe
HD: 500GB WD Caviar SATA + 300GB Western Digital Caviar IDE
Graphics: NVIDIA 9600 GT OC
Memory: 2GB OCUK DDR2 800MHz
O/S: Windows XP SP2

+1 on that the 9600gt is more power hungry than your old card.

bump