Run a scan using MalwareBytes.com (free) software and also make sure your anti-virus is up to date and run a full scan with that- do it before you go to bed and let it run all night if it has to
I use www.avast.com and have NEVER had a problem - it is my favorite (and the home version is also free)
Thanks a bunch. Guess what? I did not get that message this time!