These things can be the most frustrating issues to solve and I often wonder if I can even solve them BUT.......since you said have McAfee installed I'll start there.  What operating system and browser are you using?  Get rid of McAfee.  It is known to create more problems than it prevents and is a resource hog.  There are specific procedures you have to go through in the correct order to successfully remove it.  If you're running Microsoft Windows make sure you are using their built in security and antivirus software.  It is sufficient for 95% of all users.  I haven't paid for security software in 15+ years.  Also, your browser most likely has some sort of extension or plug in service running where you can see what your browser is running.  Look through it.  You might be surprised at the adware/malware and or advertising/data collection extensions you have running on your system.