Right-click on an empty space on the desktop, click on "Properties" then in the window that pops up, click on the "Settings" tabs. You should see two boxes representing your monitors. One will be grayed out, click on that one then put a check in the "Extend my windows desktop onto this monitor. Then click "Ok" and you should be good to go. One more thing, you can change how the monitors are arranged, click and drag to rearrange them.
\".......die screaming with sharp things in your head\"
Proud Bush supporter.