Keyboard issue

you sure you didn't get some jelly donut on there and a key is stuck? if not it does sound like bad keyboard. i would try it is Safe Mode to help confirm...
my two cents is: the keyboard is not that hard to replace if you are patient and buy a torx set for the compaqs (about $40). torx 8 is the only one you need i think but the comppaq screwdriver set has long stems on the bit which is nice. i got mine at www.impactcomputers.com
i would expect your keyboard to run about $40
don't get a refurb, is my 2 cents

First connect an external Keyboard and make sure that things like Num Lock are not activated as that will cause all types of interesting things to happen on the NB keypad.

If you do need to replace the keypad you don't need to buy a complete Torx driver set you can just buy the necessary Torx Drivers from Snap On and while you don't actually need then get the tamper proof ones as they will be more useful to you in the long run and just buy the ones that you currently need that should be a T8 driver.

But before attempting to replace the keyboard unless something has been spilt on it I would first attempt to change the drivers for it and see if that fixes the problem. NB Keyboards are generally very reliable provided that they are not subject to having things spilt on them.

Col

In the reional and language option controle pannel. make sure that your keyboard is set to your language input needs. Under the language tab.
If it does not work remove the drive for the kb reinstall.
If this does not work. hardware. test with external kb