I would need more information in regards to your system configuration:
Which version of Windows do you have?
Also, the exact processor model and the graphics controller:
Click the Windows icon, and then right-click Computer .
Select Properties .
Find System Type on the Properties window, and then note the processor model.
Can you send a screen shot of the graphics control panel? Multi monitor settings picture would be great.
See the link below for information about multi monitor configuration: