Here are some Windows keyboard tricks you can use to impress your friends! These are nothing but less known features of the Windows XP operating system. To revert back the screen to previous state, repeat the key combination again.
Trick 1 (High Contrast) – Hold Shift, Alt and Print Screen keys together. Click on “OK” when a message appears (this enables high contrast on Windows system). The screen should change to black!
Trick 2 (Magnifier) – Hold Windows key (logo key) and R key together. Type magnify in the run box and then press Enter. This enables magnifier tool and anything near the mouse trail will now appear magnified on top!
Trick 3 (Invert Windows screen) – This is one of the scariest tricks which turns Windows upside down. You can press Ctrl, Alt and then any of the four arrow keys (Ctrl-Alt-Down will rotate screen by 180 degrees)! I have noticed that this doesn’t work on certain Windows XP machines (It is dependent on video driver).
You can check out these and many more accessibility tutorials here.