Dual Monitor Woes

So I have a Desktop PC with dual ATI 5770's in Crossfire that means 4 DVI ports in the back of my tower.

My main monitor an AOC 2236 is connected to the top most DVI port.

Now I want to connect another monitor to my computer in this case a Wacom Cintiq.

I have had the Cintiq running fine but every time I install drivers it stops connecting properly to my computer. The Cintiq has a dual switch that allows it to cater for either DVI or VGA connectivity.

Now usually with a second monitor you just plug it in and extend the display. In my case when I plug the second monitor into the second DVI port my main AOC screen goes blank. I then turn on the Cintiq when it is connected and it says 'no-sync' 'go to sleep' and then turns itself off.

Now I know that's probably an issue no one can help me with but I need to get to the point where I can at least have the second monitor plugged in and be able to use my main monitor.

I have tried everything:

-Booting with the secondary monitor connected only.
-Booting with the secondary monitor in the first DVI slot, main in the second.
-Booting with the secondary monitor in the other 2 slots.
-Booting with the main monitor in the other DVI slots with the secondary in the first.

I have always had this issue with the device and it often takes hours of playing around but I want to nip this problem in the bud.

I'll try reinstalling the tablet drivers.

Thought I was forgetting something, I tried booting up the computer with both connected before and both monitors were working correctly right up until the Windows Login screen then the Cintiq just goes to sleep, while the main monitor works.

Maybe I should try lowering the resolution and trying it again?

Also reinstalled the tablet drivers without much help :P

Thanks for your quick reply btw.

Can you run dual monitors when the video cards are linked in crossfire?

Yeah I can definitely have a second monitor on my Crossfire setup I have had it working before. (both monitors in the same card).

I still have yet to boot up the system with lowered resolution. Will test it tonight as I have been busy with work.

Thanks for your responses guys.

Just tested a few scenarios before

So I had my monitor in the BOTTOM slot of the TOP video card. I plugged in my Cintiq and it came up as multiple monitors as I was swapping resolution. Which is strange because usually after plugging in the Cintiq my main screen goes black.

So I set the resolution down to 800x600 and rebooted. Same story, Cintiq was displaying fine right up until the windows login then it goes to sleep while the main monitor continues working.

I then decided to swap the two monitors cables, I put my main monitor in the TOP slot of the TOP card and the Cintiq in the BOTTOM slot. Totally different story. Cintiq didnt pick up at all and the main monitor went black as soon as it got to the login screen.

Its almost as if the computer is giving the main monitor to the Cintiq but the Cintiq isn't picking up on the connection. Cant see how to fix this.

EDIT: Just plugged in the Cintiq, my resolution changed, and it was recognized as a second monitor. I selected Extend these displays but both screens went black and then the Cintiq went to sleep. Had to restart without Cintiq connected to get back into windows.

Yeah Mike, I got to the point before where the Cintiq was actually next to my main monitor in the screen setup diagram. Changing any settings like extend display or the resolution resulted in my LCD monitor to go blank again. I tried to emulate the same situation but ended up with having one monitor box saying multiple displays and a 1/2 inside it.

I'm going to attempt to get the Cintiq actually recognized again so I can hopefully setup the a Main monitor.

EDIT: Connected Cintiq again, resolution lowered automatically. Then I used the detect displays option. The Another display detected box appears even when using my main monitor with nothing connected and using the detect function. (Sorry for the big picture).