For a few weeks, my browser (Chrome) will open itself up, and then continue opening up a new window every 3-5 minutes. These are blank windows, not even an "about: blank" in the URL window. Not new tabs--new Chrome windows. So I have to shut them down one by one, and have to turn off my computer when I'm away or I come back to many open browser windows. I've run newly updated Malwarebytes and three different antivirus programs, Registry Mechanic, CC Cleaner, scanned with Norton 360, reinstalled Chrome. Nothing works. Help!