SetupDiag will not run

When I run SetupDiag, it goes thru installation and when it runs there is a microsecond flash on the screen then it is terminated.  No errors given.  I have read many articles about this and tried everything.  II need to run this to partly alleviate other errors (like finding a bad driver) that I have gotten elsewhere.  I did update system drivers already.  No good.  I would be so grateful if someone could help me.  I am running Win 1909 Build 18363.1556 and I an stuck in this version until I can get Windows Update to work (subject of a different post).