E207WFP Monitor

For the past couple of months, every so often a menu for my monitor flashes in the middle of the screen.  At times, it stays there for several minutes.  Then I get a picture of a lock in the middle that is sometimes locked and sometimes unlocked.  Now they are staying longer and longer in the middle of the screen, which is frustrating when one is trying to surf the net or use any other programs.

Please tell what to do to stop this.  It is getting worse.