O.K. Can't remember what I put, but I have never been contacted by any method.
Will watch for any relevant reports of similar installation problems.
There is one process for uninstall/reinstall which has reportedly worked for many users who have had problems with repeated failed attempts to install on Windows systems:
1. Uninstall Virtualbox normally and Reboot;
2. Go to "C:\Windows\System32\drivers", look for any files named 'Vbox*.sys' (there could be up to 5) and delete them.
3. Reboot again.
4. If you have any 3rd-Party security or anti-malware software installed, disable the living daylights out of it for a moment. This is not necessary with the native Windows Defender.
5. Reinstall Virtualbox using right-click-Run-As-Administrator.