installed a asus radeon 7770 2gb hd in my pc with a pcie x16 slot and when i turn on the pc with the new card plugged in the power button doesnt light up but still works and my display is black ive uninstalled my drivers and idk what to do i have a 450 watt antec psu help pls and my fans spin up and the gpu light is green but if i boot without the card plugged in with the 6 pin all my stuff lights up but no boot and while the pc is on if i connect the 6pin the card is fune just still no boot