Radeon 9600, dual monitor issue

System Manufacturer/Model Number: Custom built
OS: Windows 7 Ultimate x64/Windows 8 Enterprise
CPU: Intel Core i7-2600k
Motherboard: Asus Sabertooth P67
Memory: 8 GB
Graphics Card: AMD Radeon HD 6990
Sound Card: Realtek HD Audio
Monitor(s) Displays: 2x Samsung S22B300
Screen Resolution: 1920x1080
Mouse: Logitech Peformance MX
PSU: Corsair GS700
Case: Antec p193
Cooling: Cooler Master Hyper 212 +
Hard Drives: Corsair Force Series 3 WD Caviar Green
Internet Speed: 15M down/1M up
Antivirus: Kaspersky Pure