Screen Showing Blank! Help please.

Starmaderp

Honorable
Jan 17, 2013
204
0
10,680
I've just built a new PC and I've gotten everything correct I've plugged everything in correctly but for some reason when I plug my HDMI into my TV and turn the comp on, the screen says "No Signal Detected". This isn't a new screen as I used my old computer on it so I don't know whats wrong,
 

Starmaderp

Honorable
Jan 17, 2013
204
0
10,680
Also I don't know if you need these but here are my specs

ASUS Extreme IV x79 mobo
Intel-3930k
GTX 780 (Upgraded from 670)
900W PSU

I'm using a HDMI cable that connects to my TV to display my screen.