Randomly, my keyboard types numbers instead of certain letters. For example "Keyboard typing numbers" becomes "2eyb6ard ty-5ng n40bers". After searching on Google I found turning off num lock fixes the problem but would like a more permanent fix. The keyboard is Dynex and I've tried updating the driver. The keyboard connects through a USB cable.
I recently had this issue after upgrading to Win10. My USB keyboard was working fine on Win7, but started acting out with Win10.
The numlock temporary fix was driving me nuts, but I noticed that my husband's keyboard was working fine, and the only difference was that his was a PS2 keyboard. So I took a USB to PS2 adapter and used it with my keyboard, restarted the computer, and now it's working.
I hope this helps you too!