Hi Bernard.
I have a similar experience.
My Dell laptop came pre-installed with free 15-months McAfee Anti-virus protection.
Just prior to expiry of the protection, I decided to switch over to Windows Security.
I did both methods of McAfee App Removal, i.e. the Standard Windows Removal and when I still couldn't switch over to Windows Security, I downloaded the MCPR as suggested by McAfee and ran it.
Still didn't work and Dell Support helped me to reinstall something and it still didn't work.
As a result I have been without protection for quite a number months.
What went wrong?
Thanks.
Lee