Fn+F6 works fine to disable touchpad on Lenovo G780. But when it wakes up from sleep, the touchpad is enabled again. Is there a way to make this disabling persist (without disabling the driver completely, since I may end up without a mouse sometime)?
The Synaptics, ElanTECH driver normally has this functionality. Lenovo Synaptics ElanTech driver is downloaded here for Windows. This app appears in Control Panel once installed. They have XP and Windows 8 drivers as well.