Newly built computer, monitor has no signal.

[Joycer]

Alright im building a computer and when i power it up the monitor has no signal. i was wondering what it could be. The monitor works fine on my other computer and the graphics card seems to work also. i was thinking that it may be under powered but the fans are working. i also dont hear the HD spooling up

 

[Tmagic650]

What are the complete specs of the system that you are building?