My 10 year old boy felt asleep with his head resting on the touchpad of my MBP -Touchpad stopped working properly. I wanted to check if I could adjust the touchpad in some way before buying a new touchpad.
Well it went well - although I do not know what did the fix. But I removed the battery pack, unplugged the touchpad and plugged it in again, used my thumbs to do an adjustment of the touchpad and it worked again. It saved me about $200 in spare parts, just unplugging and re-plugging.
Go on and open your devices, careful of course, do some experimentations