SupportAssist 3.13.2: Won't Run, Uninstall, or Reinstall

I've been trying for the last several days to run Dell SupportAssist (version 3.13.2.14) on my Windows 10 Vostro 15-7500 laptop. All I ever get is the message, "This is taking longer than expected. We recommend restarting your PC and trying again later." So far, this hasn't worked.

If I run the installation download file, SupportAssistLauncher.exe, I get the message that the latest version of SupportAssist is already installed. If I try to uninstall SupportAssist in the Control Panel, I get a Windows Installer error, "The feature you are trying to use is on a network resource that is unavailable. Click OK to try again, or enter an alternate path to a folder containing the installation package 'SupportAssistx64-3.13.2.14.msi' in the box below." The path to this file is:

C:\Users\[username]\AppData\Local\Temp\SupportAssistAgent\cd4af687-1452-4994-be2d-6421b9b830db\

but that directory doesn't exist. The path:

C:\Users\[username]\AppData\Local\Temp\SupportAssistAgent\77d42f07-0023-416a-9efa-f8258bc3b4ae\

does exist, but it doesn't contain the .msi file.

There is no option in Control Panel to do a repair installation of SupportAssistAgent, IMO a lapse on Dell's part.

How can I uninstall and reinstall SupportAssistAgent, so I have a working program.

Thank you.

Terry