6970 dead dvi port

hello! i have a problem with my radeon 6970 saphire since i bought it. my lower dvi port is dead. i use a single monitor and the upper dvi port & hdmi recognize it but the lower dvi just can't. i also have problems recognizign the monitor while installing windows 7. i must install it on hdmi cable and only after instalation switch to primary dvi port. if else i have no signal after windows loading file steps. it flashes on screen different collours (red, green, black, etc.) i don't know if the problem is the gpu or something else. thx for any answers that could help me with my problem. (i have an asrock extreme3gen3 as motherboard)