Asus A8N-SLI problems with 8800 GTS OC 640 meg

[niggles]

This is driving me nuts, I can't figure out why I can't get video. When I try and boot I get two regular beeps back to back and then 3 quick successive beeps. I took the first card that I had do this back and swapped it for another with no success. Apparantly this is indicative of a processor issue, whether it be GPU or CPU. my rig is as follows:
AMD 4400+
Asus A8N-SLI
Enermax noisetaker 485 watt power supply
2 gigs of RAM Kingston
250 Gig Sata2 drive
BFG 8800 GTS OC 640 meg version.. .not the 320 meg
I also have 1 more hard drive on IDE and 2 DVD drives. I unplugged all three of the other drives to try and get it to boot with no success.
I have the most recent bios 1014 running
What am I doing wrong? The power supply should be ok according to BFG, and I can't find any compatibility issues with this mobo... what do I need to do?

Thanks for your help in advance.

edit: oh, I should mention that this rig works fine with my current BFG 7800 GT OC

 

[sep]

Did you ever get this working? I've got a similar rig and was thinking of upgrading to the 8800 GTS. I've got the Antec True Power 480 and specs say I'm good. Even with the extras.

 

[niggles]

You know I considered posting back as I found out what it is... it's embarassing though... K, I hooked up the power slot on the mobo that powers the board if 2 cards are being used. I have no idea why it worked with the 7800 GT OC, but it did... I got sick of futzing about with it and took it to Canada Computer who fixed it in about 30 minutes. I think someone should take away my geek hat, or I should have to write on a board "I will check the manual" 500 times...