If two or even single finger scrolling doesn't work after update to Windows 10 and your touchpad is manufactured by Synaptics company, download and install driver for touchpad version 16.2.x. Everything will work like a charm.
Open this link Synaptic Touchpad Driver 16.2, supports scrolling on Windows 10, check "I agree" options on the bottom of page and press "Submit" button. The driver will be downloaded.
