Thank you. I did change compatibility mode when I was first trying to get the program to work again. Oddly, when I checked on compatibility in the two locations you specified, everything was unchecked already.
As for the location, I have a lousy small electronic hard drive C (this PC was made when there was a shortage of physical hard drives), so I recently uninstalled and reinstalled some programs to an alternative location in D. Would that really make a difference? As I recall, i was able to open and run a scan on Malwarebytes Anti-malware after I did that. In any case, I'm will to uninstall on D. Could you provide me a link to download the most recent paid version? (I can provide ID and key, if needed.)