Here is a link to the driver I use on my G75VW having the latest version of Windows 10:
May I suggest you download and install the latest version of the ATK driver as well:
In Control Panel/Programs and Features, is the Synaptics Pointing Device Driver listed?
In Device Manager/Mice and other pointing devices, is the Synaptics PS/2 Port TouchPad listed?
Do all the other Function Keys work properly?