Have you replaced the notebook keyboard yet? It may be the cheapest fix.
I have hp notebook ze4325us. Operating System is WinXP SP2. Yesterday all of a sudden, my computer started typing zeros (0). The zero key itself is not working. If I want to type zero or parenthesis, I cannot do that. My computer is typing too many zeros by itself. I have another PS2 keyboard. I plugged it in and for 5 minutes, it worked fine. Then the same problem started with the external keyboard too.
Does any one know how to fix the problem? I'll appreciate any help.