Peter,
I have done this already I believe earlier sometime in this thread as well as running the EASEUS sector by sector check of the HD and it has always passed, that test took hours and hours to run. I really suspect that the HD is ok and what ever the issue is with the PC I have had enough ;-)
As mentioned before this all started in late 2018 when Acronis came up with a update to the backup software, the backups would not validate and that was caused I believe that the scannow would not pass due to corrupt files.
Acronis updated to there 2 tier engineering dept who for most of 2019 just had me doing all kinds of test what one of was checking the HD for errors etc, that always passed.
Later 2019 Acronis gave up and told me to wait till they came out with a newer version of the software.
In the meantime I came across a original owner Studio 540 with all OEM Dell software included ( all specifications were the same) I purchased that w/o a hard rive and just tried installing my HD from my old 540. Well same issue.
So next I bough a new HD and did a fresh OS installation and about that time Acronis came out with a new 2020 version. The Acronis worked a few times and then failed the valuation part. I ran a scannow and that also failed with the same corrupted files.
Acronis techs looked into it again finally came up with a solution , refund my money. The software would occasionally work but mostly not.
Then I basically mothballed the PC and just kept for a backup as it could still work but just could not use the Acronis software.
So at this point after all this time it going to be scrapped, as mentioned I cant even connect with out some kine of issue.
You patience and help will never be forgotten and I did donate a few times here.
Thanks and many thanks, John