The caps lock button, which causes everything you type to be in capital letters, is often pressed by accident. The results aren’t life threatening, but having to retype a sentence or two can really tick me off. Many have looked all over the internet for a way to warn them when the Caps Lock key is mistakenly pressed.
It turns out that the answer is right inside Windows! Windows has a feature called "Toggle Keys". When the toggle keys feature is enabled your computer emits a beep when the caps lock or num lock keys are pressed, and a different beep when they are pressed a second time to turn them off. It’s a feature I enable on all of my computers.
Turn on Toggle Keys in Windows Vista and Windows 7
Type Ease of Access in the Start Menu and click the top result – Ease of Access Center, which will open the window below.
Click "Make the keyboard easier to use", which opens the window below.
Halfway down you will see a checkbox and Turn on Toggle Keys. Click the checkbox to place a check and hit apply. Now each time you hit the caps lock or num lock keys you will hear a beep.
Turn on Toggle Keys in Windows XP
Click the Start Button>Control Panel>Accessibility Options, which will open the window below.
Place a checkmark in the box labeled "Use Toggle Keys" by clicking the box with your mouse. Click OK to close the window.