Can you hold down Win+R keys, type in intl.cpl and press enter.
Then go to the Administrative tab > Change system locale, make sure the box I circled is NOT checked. Then save the change. REstart the computer and test ALT+2 again. Make sure Num Lock is on and that you're using the numeric keypad, not the number row near the top.
As the key tone issue.. I need some testing first. Can you launch on-screen keyboard, then tap on the Caps lock, or nums lock, does it make the tone for those?