key board gone crazy is
C'mon Goldy. You know we need a bit more info than that to be of any help.
Shut the computer down and then restart to see if that fixes it
If a plug in make sure the plug is firmly in place
If battery operated remove the battery and rub both ends vigorously or replace batteries
If WiFi with a separate semsor check the light is on if it has one.
Plug in not wall socket.
I realise your keyboard would not plug in the wall. However it might have a PS2 round connector, a rectangular USB connector, both of which would plug in the rear of your tower, or it might be wireless with or without batteries.
Did you try any of the suggestions I made?
Could you mean Firefox Plug-in--like adblock for example?