Dear softwaremaniac,
Again you've come to the rescue. Thank you so much for the exceptionally prompt response. It is greatly appreciated. As usual you have successfully resolved the matter -> SFC "Windows Resource Protection did not find any integrity violations".
As I suspected in March, and now confirmed yesterday, the offending program that causes the corrupt system file(s) is Horizon DataSys Rollback Rx. It happens sometimes (not always) when you "Update the Baseline". Now that I am aware of the cause, hopefully I can avoid future problems. If not, I hope you will be available to assist me again.
Once more, thanks for your time and help.