Hi guys, I have a similar problem:
Just bought a new PC, installed everything and using onboard graphics, everything is OK. If I plug in the graphic card, the computer doesn't start. The display don't turn on, the keyboard / mouse lights neither. The Fans are working (even the graphic card fans). I unplugged and replugged everything, reseted BIOS, disabled onboard graphics, but with the graphic card nothing works.
I have no chance to test the graphic card on other PC, or other graphics on my pc.
Any help ?
Thanks for your time!
XFX Core Edition PSU PRO 550W
Gigabyte Ati HD7870 OC Version 2GB DDR5 PCI-E
Intel Core i5-3470 3.2GHz (3.6GHz Turbo) 6MB BOX
Corsair Vengeance LP 2x4096MB DDR3 1600Mhz
Samsung 840 SSD 2.5 SATA III 120GB