Thanks Sam,I already got it fixed a few days ago, since my last post I was able to get SA re-installed and running.The key was deleting this directory: C:\Program Files\Dell\SupportAssistAgent. I couldn't delete it because some other programs had it open using some of it's files. Namely explorer.exe and svchost.exe. explorer.exe was open because that's what I was using to attempt to delete that directory. Closing explorer.exe relieved it's use of files in that directory, but how do you delete the directory without opening explorer.exe. That's a rhetorical question, because I found the solution. svchost.exe also had the SupportAssistAgent folder open using some files. svchost.exe is more troublesome as it can't be shut down. But again, I found one solution to deleting that directory in spite of it being used by explorer.exe and svchost.exe. I elevated to being the admin user and still couldn't delete the directory in question. After doing some research I found a way to delete that directory with another 3rd party tool. After doing that I checked the registry (regedit) and found no instances of SA or PC-Dr.   So I was good there.  Oh, and prior to doing all that I downloaded and ran the Dell OS repair and recovery tool.  I didn't do a clean  Win10 install, I just ran a repair diagnostic that found some HDD errors and fixed them but that didn't help with the re-install of SA. After finally deleting the SupportAssistAgent directory I re-installed SA and I can now use it when needed.   There a 2 remaining issues with my laptop that are inconsequential to me. The strange thing is that SupportAssist has not diagnosed them or even found them to be out of whack. 1. My integrated camera is not working. SA does not diagnose that after a hardware scan. But the fact of the matter is that it does not work. I never use it, so to me it doesn't matter. 2. My LAN (ethernet) adapter only downloads from the internet at 20mbps on a network where all my other devices download and upload at 100mbps.  The strange things is that although my Dell laptop only downloads at 20mbps it uploads at 100mbps.  So I know there is something amiss with the LAN adapter.  Also, not an issue since this Dell laptop has become a backup and I only use a wifi wireless connection when using it.  I get a faster wifi download than I do with an ethernet connection. Using other software to diagnose hardware issues shows that there is a failure with the LAN adapter. So even though SA is running, it's usefulness to detect and correct problems is questionable, similar to the usefulness of the responses I get on this Dell forum.  
Read this thread:  [URL]#M86420 At one point a Dell moderator says that Dell knows about it and is working with Microsoft to fix it. And????????? About 70% of the posts on the first 2 pages of this forum are about problems with SA not working, not installing, not completing an update. If you read the above thread with a sense of humor you will get a kick out of the screen shots that one Dell moderator included that no one can see.  And nothing is even done to display those screen shots even though several users asked if they could be shown. Don't worry about not being able to see the screen shots, that solution doesn't work anyhow. There are a few implications from some of the moderators,  that if you have a Service Tag number that shows warranty coverage, Dell will fix the problem.  If not under warranty you can ask for service quote to pay for the fix to the problem.   You have to admit those kind of responses from Dell moderators implies that there is a fix, but you won't get it fixed unless you are under warranty  or you pay for it.  That's a very disingenuous (if I didn't spell that correctly just substitute 'DISHONEST') position for Dell to take.  Why do you roll out software updates, driver updates, etc on unsuspecting customers?  You know that if there is a problem, only customers under warranty  or willing to pay can get a fix to the problems that the updates created.  Your updates should not be automatic after warranty coverage has expired, and should come with an appropriate warning: "Update at your own risk, if a problem results, you will have to pay to fix it, "  After the multitude of problems I've had with my Dell laptop due to Dell updates and/or Microsoft updates, I went to Best Buy shopping for a new laptop.  I asked the salesman for a recommendation, all he said was "I hate Dell"
Dell has ignored SA problems for almost a year!