I was working an older computer yesterday and had a similar problem. Except I had a picture 2 Times out of about 10. Well I noticed on the post screen it said there as 2 x 256 sticks of ram. When I looked inside I saw 3 sticks, one was 512. Well I took that out and everything is good now.
You probably didn't build the computer right. Not trying to be an ass, but if you plug in the monitor and there is no signal, could be any number of things. It doesn't have to be video card/monitor specific. Need more info of what exactly happens, any sounds, lights, etc.
Is you're monitor an ASUS. Every once in a blue moon my monitor will go through a fit where it won't display anything. I would normally restart the computer and it would sort itself out. Not sure if it was a GPU or Monitor issue.
Has it ever displayed for your current config/setup?
LOLing Michigan since Sept 1st, 2007 "I believe the best social program is a job" -Reagan