Originally Posted by munkus
So you're asking why you can only see stuff on the monitor when it's plugged into the computer?
Nope - what he means to say is that the startup sequence is displayed on the monitor when connected to the Video Card's VGA out, but once logged in he needs to switch to the integrated gpu's VGA out in order to get a picture.
OP- You need to go into your bios and disable the integrated GPU. That should solve your problem.