HD 4850 Not Posting!

Long story short:

Computer was getting dusty inside so I decided to clean it out. Was out of canned air so I used a brush and vacuum (stupid but ive done it before with no issues). Graphics card was really dusty and I could not get at the cooling fins and fan. So i took it off and took off the heatsink and cleaned it; if damage was done, i think this is where it happened.

I installed the video card and in a rush to get online, I forgot to insert the 6 pin power connector. So it booted up but nothing appeared on the screen. I moved the VGA line from the video card to the on-board video card and all was good.

I powered it down, connected the 6 pin connector to the GPU and fired it up. Nothing. no post, black screen. All the fans run (case, CPU, GPU). The CPU is slightly warm to the touch, the GPU also seems to have some slight warmth though its so minute its hard to say.

To clear it up, it runs fine with the HD 4850 out of the system but when its in and I try to boot up all fans run but there is no other life signs outside of that.

I have cleared the CMOS and such. Messed with numerous bios settings and have not had any luck.

My setup:

m4a785-m motherboard
athlon 630 quad core
sapphire hd 4850
antec 550 PSU
WD 750GB HD

Anyone have any suggestions?

I dont want to buy a new one when it could be something simple, atleast thats what im hoping.

Try installing the 4850 on the other CPU. If it works fine there, could very well be your slot is damaged.