OK, I'm going to ask one more time, just to clarify for myself:
Did you uninstall the DEVICE ITSELF in Device Manager? [And you may have]
Uninstalling/reinstalling the device driver software is, upon rare occasion, not enough. It is unclear to me if you intentionally made the operating system believe that the device itself was no longer present, first, before uninstalling the existing driver software, doing so through Programs and Features for good measure (as I've always seen the Synaptics Utility show up there).
Everything I'm seeing here suggests corruption of some kind and that this corruption is not being removed in its entirety before new software is installed, and the new software is using the corrupt bit from the previous installation.
I'm all out of ideas if you are absolutely certain that you have done a complete purge of the existing software prior to reinstalling. The only other thing I could suggest is trying something like Revo Uninstaller on the Synaptics software before reinstalling again, which should definitely purge any trace from your system. If that doesn't work then I'm absolutely out of ideas on this one.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
. . . the presumption of innocence, while essential in the legal realm, does not mean the elimination of common sense outside it. The willing suspension of disbelief has its limits, or should.
~ Ruth Marcus, November 10, 2017, in Washington Post article, Bannon is right: It’s no coincidence The Post broke the Moore story