HD4850 died? help.

Hi im just new here. & this is the problem, I believe my powercolor hd4850 died already. Under normal circumstances everytime I start my computer I can hear my Hd4850 fan running I believe at 100% fanspeed (its loud) but it only lasts for about 2-3 seconds but the fan goes back to normal when the monitor finally shows info and starts to boot up. That has been the case for the last 6 months, but its ok. So is that normal?

But last week, when I open my computer, all that I hear is the loud fan from my HD4850 and it doesn’t boot up. I removed the card and plug the monitor to the on-board video & my cpu starts normally again. I put it back, & again all that I hear is the loud video fan & wont boot up. So definitely my HD4850 is the culprit why it doesn’t start.

I have a Gigabyte Superb 550, 450 watts psu.
Core2duo E8400 no overclock
2 gig
Asus p5kpl g31 mobo.

Im just a noob actually, I have very limited idea about that bios thing. I want to know how I can fix this thing or what could be the reason?

Thank you in advance.

Try checking the card in any other computer.
See if it works...........