check if the 7970 is deeply and tighlty fixed in its slot
how do you connect the monitor to your graphics card? Adapter used? HDMI, DVI, VGA, DisplayPort?
Already checked and i have changed the slot also.I use HDMI. My previous monitor was with dvi.When i connect both monitors (old and new) vga led is clossing and i can see bios only with my old monitor