After being in Safari for 5 minutes or so, it turns to white with "Loading…" printed in the middle of it. Trying to go back or undo does not work. After about 10 seconds, I get a smaller screen that says "Installation Complete…The configuration process is done. To finish, press OK". See screen shot below. My cursor is stuck and won't move. I was able to force quit Safari, Mail, etc., but, that did nothing to get rid of this screen. I wasn't installing anything and even if I was, the cursor won't even move to the OK button. I think this is malicious. Eventually, after several minutes, it disappears. Any ideas on how to keep this from happening?