x850xt problem

I bought this card about a year ago from overclockers, ran fine up untill 2 days ago. When i was browsing the internet the graphics card fan (well im assuming it was the graphics card) started speeding up and making a very loud strange noise. The computer froze and the screen went multicoloured. I had no choice but to switch it off by the plug as i was worried it would blow up!!! (thats what it sounded like!) When this happened i left it for a few hours, it was never really the same, when i went into games it just froze. So i decided to open the catalyst centre and run a scan, it came back that the card reached 85c before the computer just shut down so i assumed that it was the graphics card that was malfunctioning and overheating. Which made me assume that it was the graphics card that was making the noise before.

Well the computer kept crashing, butnow i cannot even boot the computer now. I turn on the computer and all i can hear is the graphics card fan. The OS doesnt boot, all that comes up is a black screen. The diagnostic lights on the back of my dell 8400 tell me its a pre bios error (no lights are on).

Recently I had hard disk failure, so i had to get a new harddisk and reformat. I installed all the drivers, (catalyst 6.11) fro the video card. I assume that wasa all i need to install for the video card. I also installed a sound driver, printer driver, internet drive... and i think that was all...

Any help would be appreciated. Thanks!

emm... well i dont know if i can plug in the monitor anywhere, well i cant find anywere... and no i cant get into the bios anyway. Well the computers been sent off to dell anyway, lets see wot they can do wit it! may aswell get my warrantys worth! Thanos for the reply!