8800 GTX stopped displaying on sceond monitor

[Master Skooter]

I have a Dell Inspiron 9200, running a 8800 GTX dual displaying onto two 19" TFTs.

This set up has worked fine for a number of months, and does so on duplicate set-ups.

However recently the machine no longer displays onto the second monitor. Swapping the monitor cables over shows that both monitors/cables are functioning correctly.

I have tried another 8800 card from a different working PC, but the problem still persisted. Strangely when trying a lower spec 7950 GX2, both monitors display perfectly.

I've also tried the original GTX in another Dell 9200, but this also only displayed on a single screen at the POST screens (where as the 7950 displays on both). The PC has no HDD, so I couldn't boot it into an OS.

Initially you suspect that the card is faulty, but it's odd that a second fully working 8800 also fails to display onto a second monitor. I'm a little lost as to what is casuing this problem. I would try a quality after market PSU, but it appears that the connectors are different. Good old Dell eh.

I was wondering if anyone had come across a similar issue before?

Thanks.