Computer wont boot when only connected to WG monitor. Win7, J-Pac, ArcadeVGA 5k

[Sideshow]

I'm having a really weird issue getting my friends system to boot when only connected to the arcade monitor. It needs to have an LCD connected or it refuses to boot. Here is what i'm dealing with:

Win7 64bit
ArcadeVGA 5000
J-PAC
Wells Gardner 25K7193

I have no idea whats going on with this computer. When only the arcade monitor is connected i can see the POST, but then the screen will get distorted and then nothing.

When i have the regular computer monitor plugged in, it uses the monitor to display POST info and then once the win 7 screen passes it switches to the arcade monitor and there are no problems.

I've disabled the Win7 logo on boot but have no idea what else I should try.

[Generic Eric]

Do you have to change the video out into bios?

[mgb]

Sounds like maybe a monitor detection issue.

check out this post. The op states what sounds like a similar problem.
http://forum.arcadecontrols.com/index.php/topic,141799.msg1467814.html#msg1467814

[Janecorec]

Did you ever get this sorted out?

I'm having similar problems whit my setup. Haven't tried installing the ArcadeVGA yet, but the weird thing is that it worked earlier (only had tried it out a couple of times) but then the main power button broke and I had to replace it, after that...I can see the post messages and then it gets all scrambled and when windows is started the screen goes black.