So, open up a program (just about any one will do), and hold your Windows key ( the Windows key is the one located between your Ctrl and Alt keys on your keyboard and has the Windows logo emblazoned on it).
As I said, hold your Windows key and press one of the direction arrows on your keyboard.

Windows Key + Left Arrow – Snaps the current window towards the left side of the screen.
Windows Key + Right Arrow – Snaps the current window towards the right side of the screen.
Windows Key + Up – Maximizes the current Window.
Windows Key + Down – Send the current Window to a compact state. Press again to minimize. Note: Once the window is minimized, you need to click on it again if you want to access it.
Remember: This trick is only for Windows 7 users. Everyone else is just going to have to use their mouse, I guess!
~Andrew

