RADEON 5850 Wont Post

So I just got my new RADEON 5850 and attempted to install it into my machine to replace my old 8800 GTS. Problem is I get no display and no POST *beep*, I tested the card out in two other separate machines which both work fine so its not the card. I figured then it might be I just dont have enough power as I am only running a 500W even though the recommended is 500W, went out and bought a 650W but the issue continues. The computer runs fine if I put the old card back in no problem.

Now I have been reading all sorts of posts from people who are having the same issue as me, some of which have the same motherboard, I get a few saying a BIOS update should fix the issue while others are saying the card is not compatible with my chipset. I would like some suggestions since I sunk 300 bucks into this card and its a little more then frustrating not knowing why I cant get this to work.

My system is as follows.

Operating System: Windows 7 Professional 32-bit (6.1, Build 7600) (7600.win7_gdr.091207-1941)
Language: English (Regional Setting: English)
System Manufacturer: NVIDIA
System Model: NVIDIA nForce 590 SLI
BIOS: )Phoenix - Award WorkstationBIOS v6.00PG
Processor: AMD Athlon(tm) 64 X2 Dual Core Processor 6000+ (2 CPUs), ~3.0GHz
Memory: 3072MB RAM
Available OS Memory: 3072MB RAM
DirectX Version: DirectX 11

If anyone can provide any clues or better set solutions I would be much appreciated.

Thanks.