Open two or more programs.
The last program that you open is the active program.
You move from one open application window to another.
Press and hold Alt+Tab.
A small box reveals all opened programs.
Release the Tab key but keep Alt pressed down; press Tab until you reach the program you want.
Each time you press tab, you cycle through the icons representing open programs.
Release the Alt key.
Windows 7 switches to whichever program is selected.
To switch back to the last program that was active, simply press Alt+Tab.
That program becomes the active program once again.