(1) If there is a VGA connection from the video card to the monitor available, give that a try. It would likely result in the same issue if the HDMI and DVI cables have no signal from the video card.
(2) Try another PCI-e slot for the video card, if there is a second one on your motherboard.
(3) If you can borrow another video card, try that in place of your current one.
(4) Make sure all your power cables are connected to the motherboard and the devices (video card needs external power too). It's easy to forget about the CPU power cable.
(5) Pull all hard drive connections off and see if it will let you get into the BIOS.
(6) If all else fails, try pulling out the CPU and reinstalling it again.
As Albert Einstein said, "I could have done so much more with a Big Al's Computer!".