Once nice feature of Windows 7 is the ability to “snap” a window to either side of the screen. You simply drag the window to the side of the screen and it will “snap” to that side. This allows you to fit two windows side by side on the screen. It’s great for when you need to edit multiple documents at the same time.
The problem is, when working with multi-monitor setups, the snap will not work properly on the border between monitors. The window will just pass though to the next monitor instead of snapping. What you need to do in these cases, is use the keyboard shortcut Win+left arrow or Win+right arrow. This will allow you to snap to the border between monitors.