New video card, no signal. Help?

Hello all, I just recently decided to upgrade my pc's processor and video card. Well, I uninstalled the graphics drivers and plugged my shiny, new parts in...only to receive no signal or power to my monitor, mouse, keyboard, and the cd drive won't open. What have I done?

The old parts were a phenom II and gtx 580. The new parts are an 8350 amd and a gtx 970. I'm running them on a 1200w power supply and 6 gigs of ram. I believe the mother board is a gigabyte GA-990FXA-UD3. It's connected by a VGA cable.

All the fans are running on the card and power supply, and I've tried reseating the card in multiple slots, as well as switching back to the old hardware. Even with the old parts, it won't boot.

Update: Just tried reseating all of the ram but still no dice. I also tried clearing the Clos but nada.