site:tomshardware com dual monitor setup ati 6850 with vga

Are you connecting both monitors to the same video card? Not all DVI ports on some video cards can handle the analog conversion required for use with the DVI/VGA adapter. This is likely your issue.

Do your monitors support DVI? If so, just using DVI will solve this problem AND will improve monitor performance (refresh, image quality, etc) over an analog connection.

Yea, both monitor are connected to the same card, I think they both support dvi but it comes with the vga cable. I will get a dvi cable to try it out.
One more question, can I get both monitor running on each card?

You can connect both monitors to one video card or two. Usually you only connect to one of them in the event you need to disable one card for apps that don't play well with CrossFire.

What specific make/model of HD6850 do you have?

I have a 6850HD by Sapphire and another 6850HD one by Visiontek with Ati Catalyst Control Center 11.5v
Currently running on Windows 7 64 bit

As I mentioned earlier, only one DVI port on each of the HD6850s is the necessary DVI-I port capable of performing the analog conversion needed to use the VGA adapter. The other DVI port is DVI-D (digital) and it can't be used to convert an analog signal.

Going with DVI cables will take care of all of this. Good luck!

I just got the DVI to DVI cable and you are right, VGA to VGA cable does not work for multiple monitors. Now I am running on dual monitor without problem.
Thanks a lot! 

Awesome! Glad you are up and running as intended. Good luck!