Dear scottgus1, it is possible that other posters may be at least as clever as you. In writing
run VirtualBox-5.1.8-111374-Win.exe as Administrator -->
I thought it would be apparent I had used "run ... as administrator" which is only available from the right-click menu.
A quick list for others reading this (let me know if you are too confused to go on):
- installed as User, ran as User,
- installed as User using (right-click) "run as administrator", ran as User,
- installed as User using (right-click) "run as administrator", ran using "run as administrator"
- installed as administrator, ran as administrator
- installed as administrator using (right-click) "run as administrator", ran using "run as administrator"
- installed as administrator, restarted, ran as User
All with same error message as original post.
If you have a working program, can you recall what rights you installed and run it on. Thanks.