Activision does not officially support the use of multiple monitors. We do not test on multiple monitor systems and cannot guarantee any level of functionality. This also includes SLI and Crossfire videocard setups.
Many games will not function properly on systems with multiple monitors. Common problems include crashing, failure to launch, or image distortion. If you are encountering any of these problems and are using multiple monitors you will need to disable the extra monitor(s) through the software for your video card or by physically disconnecting them from your machine.