|It may be that the pad has failed... (By pad I mean the touch pad...)|
It 's just possible that something is stuck underneath the faulty button. With the battery and mains power removed, carefully inspect around the button to see if there is anything there that shouldn't be?
A "very" long shot... remove the battery and mains cord; then press and hold (for abut 20-30seconds) the on/off button. Then release and replace battery. Power up and see if the problem persists. I seriously doubt "this'" suggestion will be effective; but it's worth a try.
Presumably using a usb mouse things work OK that way (i.e. the mouse will work in place of the touch pad)?
You "might also try uninstalling the touch pad and then re-installing it. Exactly how you go about may depend a little on the actual make/model of your laptop; and also the actual touch pad involved. Many are Synaptics, but there are several others too. So what make/model is your laptop?
Edited to include "my definition of "pad"...
message edited by trvlr