if you’re still using Internet Explorer as your main browser I would highly recommend switching to Chrome or Firefox,
I have been to 2 different customers today using Windows 7 and Internet explorer 11 and they’re both getting pop ups while browsing innocuous websites warning them of viruses.
I have scanned both machines with and nothing has shown up, I have also checked DNS settings and they both use different service providers. The only link between the 2 was the popup’s were identical (see photos) and they were using Windows 7 and internet Explorer 11
I can only guess there has been a possibly security breech with internet explorer, no problem were observed using chrome.