Hello and welcome to the windows7forums.
In order to troubleshoot your problem we need to know more detailed specs of your system hardware.
1. Go to Start > Run, and type msinfo32. then expand the Components tree and choose a device
2. Go to Control Panel > Device Manager and look for any entry that has a yellow flag beside it.
3. Download System Information Viewer
4. Download PC WIZARD 2008
5 Please fill out your computers specs in the User Control Panel here on the site as well. It will then appear next to your name. look at my posting and you'll see the drop-down arrow.
Your video card make and model would be most helpfully along with your motherboard specs.
What type of cabling are you using on your monitors