Hi Christine,
Thank you for your reply.
I did find a solution on Lenovo's website, which they don't make very prominent. It took quite a while to find this.
After updating the drivers, uninstalling and reinstalling the touchpad, neither of which worked, I did the following:
Turned off and unplugged the laptop.
Pressed "fn+s+v" for 20 seconds.
Pressed the power button for 30 seconds.
Then turned on the laptop.
That procedure worked perfectly. Hopefully anyone reading this post and has the same problem will be helped by it.
Berj