Ok Phil. My son has Windows 10 on his laptop and I tried to perform the same steps. There is a little difference and several extra steps need to be taken. Here we go. Click on your Window button down on the far left corner. A small window will open and you will want to click on the Settings, One you click on the settings a new larger window will open, now click on Devices, now another window will open,beneath devices you will then click on Mouse & Touchpad which is to the left, the window will now show details about your mouse and touchpad, you will want to scroll all the way down to related settings, right beneath that I want you to now click on "Additional mouse options", a new window called Mouse Properties will open, you will now click on the tab that says Clickpad Settings, it will look like this, I already have my settings saved. But you will need to click on the tab in the box that says ClickPad Disable, a small warning window will popup telling you that You are about to disable the only active Synaptics pointing device, click OK. Now you will also want to check the little box that says, Disable internal pointing device when external USB pointing device is attached. Once you have made those 2 changes you will click on Apply. Don't forget to hit Apply. Hopefully this will work for you. Many have stated that once they turn their computers off they have to go through the whole process again. I never upgraded to Windows 10 so Windows 8 saves the changes permanently.
I hope this helps you out.