The touchpad stopped working. I already looked in the Device Manager and only the external mouse shows up under Human Interface Device and Mouse and other pointers. In Control Panel | Mouse, Device Settings tab is present but nothing shows up. My idea is that if one of the System devices is related to the touchpad, that I can try a trick that has worked with other devices ...uninstall and scan to let the drivers be reloaded. I've contacted HP and they've had me install driver software and also I've removed the battery and powered on with only AC. The touchpad point is still not working. I've set up a service repair to send it into them but I've determined that I can fix it.