Asus CM5570, 3 Monitors? HELP!

Hello,
I currently have 2 monitors set up with my Asus CM5570 Computer. I would like to set up a third. I have tried to do this:
First Monitor: HDMI
Second Monitor: DVI
Third Monitor: VGA
That did not work. Either why I did it, the 3rd monitor did not show up.
How would I go about putting 3 monitors on my computer?

Thank you.

Lordbob75 said:

I believe that your video card can only output to 2 monitors even though you do have 3 ports.
You would need a second video card to run a 3rd monitor.

~Lordbob

I have tried with a 2nd card but it only had 2 VGA ports on it and I could not get the computer to output to both the on board an the card.

Lordbob75 said:

The onboard video will not work if you have a graphics card. You need 2 separate graphics cards.

~Lordbob

I thought I already tried that. So if I have a PCI card that has 2 VGA outputs, and a PCI card that has 1 VGA output. You are telling me that if I connected those it would display on all of them?