Nvidia 6600 LE not detected!!!

HI I HAVE A PROBLEM...I HAVE AN INTEL D915 GAG MB AND A GEFORCE 6600 LE GRAPHIC CARD...

MY SPECS R AS FOLOWS....

3.0 GHZ P4 PROCESSOR
160 GB SATA HDD
GEFORCE 6600 LE 256 MB PCI-E CARD
512 MB OF RAM
400W PSU

MY CARD HAS BEEN WORKING FINE FOR OVER AN YEAR, AND SUDDENLY ONE DAY THE DISPLAY ON THE MONITOR WENT OFF...IT APPEARS AS IF ITS LIKE IN STAND BY MODE...I TRIED EVERYTHING FROM UPDATING THE BIOS, RESEATING THE CARD, CHANGING THE VIDEO IN BIOS TO PCI-E ETC..EVERYTIME I TURN ON MY PC WITH THE VGA CABLE OF THE MONITOR CONNECTED TO THE CARD EVERYTHING BOOTS UP FINE, HDD Etc.., THE FAN ON THE PCI-E CARD RUNS BUT NO DISPLAY ON THE SCREEN....WINDOWS IS NOT DETECTING MY CARD AT ALL...WHEN I TRY TO INSTALL THE DRIVERS I GET A MESSAGE THAT NO COMPATIBLE HARDWARE FOUND, THOUGH MY CARD IS CONNECTED...I DNT KNW HOW TO GO ABOUT THIS..PL HELP..

I SENT THE CARD TO THE MANUFACTURER....THEY SAY IT WORKS FINE...BUT I DNT BELIEVE THEM...IT SEEMS LIKE THEY HARDLY DID ANYTHING AS THEY GAVE IT BACK TO ME IN NO TIME...NOW I HAVE GIVEN IT TO MY FRND TO CHK IT OUT IN HIS PC...WILL GET TO KNW THE STATE OF IT TOMORROW...WELL ONBOARD GRAPHICS WORKS FINE...NO PROBLEM WID THAT...ITS JUST WHEN I CONNECT TO THIS CARD I DNT GET DISPLAY...