I discovered the problem.  The earlier versions of SupportAssist installer Support assist remdiation service as a separate package.  Newer version do not not but the transition packages did a rotten job of cleaning up.  If you remove Support Assist Remediation and SupportAssistant then reboot, the re-install the latest SupportAssist, the problem seems to go away - it has been a week.
Problem 1: - SupportAssist auto-installed and resulted in a non-working state.  Uninstalled and downloaded manual setup.  Now it works. Problem 2: - Application event log gets one 1035 MsiInstaller event for each application on my PC every few days.  This reflects msiinstaller re-verifying and re-configuring each application.  It typically results from a badly written application or policy - see ([URL]   If you look around, you will see that this is a hazardous condition that can result in one or more applications becoming crippled and is to be avoided - Microsoft explicitly recommends against doing this. (I worked  for 12 years as a software developer building and modifying  msi-based applications and I can attest to the relative fragility of msi verifications and the potential for unintended effect.) This has been the behaviour with SupportAssist for the last year or so.  I used to disable Dell SupportAssistRemediation service as well as the Dell Vault related services and that cleared the situation with zero apparent effect to my system support i.e. the functions I care about continued to work (driver updates) and I have no idea what functions may have been impeded by my doing this as I did not care about them. With the latest version 2.2.0.253, if I disable these services, after a full shutdown (not the abbreviated shutdown that the shutdown button normally invokes but by running "shutdown.exe") then on reboot SupportAssist asks for admin permission to change my system.  Interestingly enough, those changes do not include re-enabling the services. PC Doctor (software underlying SupportAssist) is way too intrusive. I would never trust a 3rd party app to perform some of the operations made available via SupportAssist (e.g. cleaning up files) without more documentation as to what they do. I want a basic support facility that tells me when an updated driver is available.  That's pretty much it.  Ideally it will give me the option to install it explicitly (as does Support Assist) and would never automatically install anything.    If I ever have a system problem, I would like a comprehensive diagnostic that I can invoke as needed.  I don't want umpteen services running all the time just to accomplish these limited functions.  The new SupportAssist version now does all sorts of configuration on boot up.  I want my support tools to simplify my system management, not the converse.  And I certainly do not want them to increase risk of problems.
MsiInstaller Event 1035 Problems with Support Assist 2.2.0.253