Display is not coming

My computer shutdown automatically.
Later I tried to switch on the machine again but it (CPU) gave 1 long beep and then 3 beeps.

On monitor, it shows that it's trying to find signals (showing HDMI - Digital - Analog) and then monitor goes to standby.

Open the case and found that display card's (8800GT) is stopped and its not working at all.
Remove card and clean it. Still fan was not moving. Clean fan properly and used WD40 and fan started working now.

Placed card back and cabled. But still machine is coming up but there is no display. CPU is still giving 1 long beep & 3 beeps and monitor still showing HDMI - Digital - Analog.

I wonder if GPU is dead!!! But how come fan is working. Do i need to buy new GPU now. Pls help.

Post your complete system spec's.

spec is like this:
cpu: c2q 6600
gpu: 8800gt
mobo: asus p5q
audio: using creative audiog 2 for 7.1
4gb ram
320gb c:
2tb d:
lg dvdrw

it's not under warranty as it ran fine for 3 years. i wonder why mobo didn't give any warning. like whenever gpu was getting over heated, mobo used to give beep. and if it shutdown when gpu is dead then it should shutdown when gpu was getting over heatup.

i don't have any manual since this machine was assembled 3/4 years back. i can't find anything immediately.

i am not in position to buy any expensive card now. could u please suggest what DX11 card can be fit on my mobo now.
thanks.

ok. i got response from most of forums that it could be GPU.
well, I am going to confirm this by installing some other card on my machine and try my card on some other machine.
now, if it is really GPU then i need to buy a new display card. Please help me find good DX11 card based on my mobo / sys config.
please help me and let me have list of few DX11 card with rating.
(ASKING LIST OF FEW DX11 - SO I CAN CHECK MY BADGET)