I have a Vostro 14-3468 running Windows 10.  In order to troubleshoot a keyboard issue (see separate post), I uninstalled the touchpad driver, thinking that it would be easy to re-install.  I'm temporarily using an external USB mouse.  Unfortunately I'm now unable to get the touchpad to work at all. 

The machine behaves as if it does not have a touchpad.  Selecting   'Contol Panel / Hardware and Sound / Mouse' brings up the 'Mouse Properties' window.  I think that window should have a 'Touchpad' tab, but it does not.

Downloading and installing the Dell touchpad driver from the website has no effect.  (File 'Dell-Touchpad-Driver_9NNK9_WIN_19.2.17.70_A11.EXE.  Installation proceeds to completion and reports success.)  At the end of installation, I get a message saying that installation of Synapics drivers is not necessary.  I am not sure what the original driver was; it might have been from Synaptics or it might have been built into windows.  The original driver files must still be on the machine, but I'm not sure where.

Can anyone help?

---Larry