This is my first post, I hope it goes well.
The other day, I repaired a laptop for a friend of mine. It is an HP Pavilion zv6015us. When he brought it to me, pressing the key 5 on the keyboard would cause the machine to do very strange things, sometimes crashing the computer. To test it out, I would open notepad (windows XP), and press 5. Several characters would show up, including the time stamp (to get time stamp in notepad, press F5). Half the time the computer would lock up. So, I plugged in a USB keyboard, and the 5 key on the keyboard worked without problem. I ordered a new keyboard from my distributor, and installed it. To verify the keyboard, I pressed every key on the keyboard and it worked fine. This was two weeks ago.
Earlier today he brought it back with the origional issue; the 5 key was causing problems. Sure enough, the problem still exists. I know it is possible to have received a bad keyboard, but what are the chances of both keyboards showing the same problems? I have a feeling the problem may be with the motherboard, but I cannot prove it.
About me: I work at a computer repair store for over two years. I have replaced many broken machines ranging from MS-DOS to Vista. I know much more about hardware repair than software repair. Studing A+ and CCNA