Here's a sticky for troubleshooting:http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems
Also I would make sure the card is fully seated in the slot. Double check to ensure the video power cable is inserted completely.
The monitor says no signal, yes? How are you connecting the card, DVI or HDMI?
So no video at all during post, correct? Try connecting some other way to monitor, and make sure the monitor is reading the correct input.