If you be possible to press Caps Lock key accidentally bounty then here is a design for you. Here shown how to create PC beep and flash every time you press Caps Lock key.

1. Go to Start, Settings, and Control Panel. Double tick Accessibility Options Icon.
2. On Keyboard tab, ensure the Use Toggle Keys checkbox.
3. Then click Sound tab and ensure the Use SoundSentry checkbox.
4. Below choose the visual warning you will decide Flash active window.
5. Press Ok and you are finished and set to try it out.