8800GTX and 939 mobo

Hello all, this is my first post on these forums so be gentle I have just upgraded to a Nvidia 8800GTX 768MB GDDR3 Dual DVI PCI-E Graphics Card (from 7800gtx x2 in sli) and installed it today but after I booted up for the first time everything seem to boot fine but I cant get an output to my monitor so Im begining to think that maybe my motherboard might not be compatable or else my new card might be faulty (I have no way checking it), my spec is :-

Mobo :- Abit AN8 Fatal1ty nForce4 Sli socket 939
Cpu :- 64 bit 4800+ Dual core
Psu :- Tagan TG580 580watt Sli compliant Silent PSU
2 gb ram

Any help will be gratefully appreciated,

Regards.

Hi praeses and thanks for the reply Im not sure of the amps but I think its 20amps to each channel @12v you can see the spec of the psu at :- http://www.chillblast.com/product. [...] bestseller
its the Tagan TG580-U22 I have a photo of the psu but not sure how to post it !
it also has a switch on the back which allows you to sellect a split or combined configuration if this makes any sence
Here is some spec I found on it :-

Product MPN
MPN TG580U22
Key Features
Wattage 580 Watt
Compatibility ATX 12V
Power Properties
AC Input 115V @ 10A, 230V @ 6A
DC Output +3.3V @ 26A, +5V @ 30A, +5VSB @ 2.5A, +12V @ 20A, +12V (2nd) @ 20A, -5V @ 0.8A, -12V @ 1A

Hope this helps

That psu is stretching it close, only 20 amps per rail. Im pushing 19 per rail, using an opty 185, and Im running damn close as well. BUT, the GTX draws ALOT more power than the GTS 320 in my rig, so it could be very likely your psu

The psu has a combined 12v max of 35amps and a total 420watts (according to the diagram on the side of the psu) so maybe it’s not quite enough power? (Grasping at straws here )
Yes both PCI-e connectors are connected and I’m not getting any beeps at all, but I am getting a post code CF if that helps?