touchpad does not exist? yoga 2 pro

yoga 2 pro touchpad does not exist in the device manager list?? it did exist, not it has gine? I was trying to upgrade the device driver - same problem as a lot of others with intermittent toichpad operation.

So now, I look at the device driver list ans there is no touchpad device. I tried to search for hardware changes, but still no touchpad.

I plugged in a usb mouse and that gets recognised. but still touchpad.

any suggestions?