7970m in MX15 card problems

Bought a used 7970m to replace 260m and when it starts, there are 2 yellow vertical columns down screen. Then it has graphics like pink and blue ! all over screen. When I try to flash vBios, I keep getting bad file on command. I can post a pic on here to show what it is doing. Please any help is greatly reeived. My son save his Christmas and birthday money for the upgrade. See my boat I'm in.