Discrete graphic card can't start up?

[minibot7]

My discrete card (geforce 8400 gs) can not start up when I turn on the computer even after I disable my integrated on-board card. Please help me!

 

[Deemo13]

Maybe try to re-seat (take out and put back in) the card. Is the video going through the onboard?

 

[minibot7]

Yes, the onboard always works. It's just that when I try to connect to my discrete there's nothing but a blank screen.