Delete/repair didn’t work in Programs and Features so I went for your solution Eddie.

This worked in that I got rid of the existing install and successfully loaded a new one. I can now get Safezone to work without the error message. Thanks for the help with that Eddie; much appreciated.

I do have one problem and I think I can see why it is happening…
My paid subscription still has 87 days to run, but when I entered the number during the install it printed it in Red and wouldn’t proceed beyond that point. I backed out and next time round asked for a trial subscription. I think the reason is that I have Avast Pro installed on the allowed two computers. This is one of them and I am reinstalling to overcome the Safezone problem. Is there a way around this?