I wanted something to give a displayin the system tray for caps lock and num lock, since my cordless keyboard doesn't give such an indication. (I presume no cordless keyboards do?)
I's free to try, and only about $5 (dollars) to buy.
It's not invasive on the system at all. It runs without needing to be "installed". You can make it run at startup. It will, if you choose play some audio each time the num lock or caps lock is pressed.
I think you'll find it's just what you need.
Hope this helps,