iTunes Won't Recognize My iPad

I've been syncing my iPad to iTunes for several years with no problems. When I tried to sync this morning, iTunes will not recognize my iPad, regardless of what I try. My backup and apps are still there, but they just will not connect. I'm running an iPad2, iOS 9.3.1. I allowed an update of iTunes in the past week or so, but I'm not sure that's related. Current iTunes is 12.3.3.17, installed on a PC with Windows 10. The device icon does not appear in the iTunes header bar menu.

I've tried:

Rebooting both iPad and PC, with no help.

Uninstalled and reinstalled iTunes with no help.

I'd appreciate any suggestions. Thanks very much.