Menu box keeps flashing up on screen all the time

Check to make sure that your menu button isn't stuck on either the TV or the remote. If it is not stuck on either of them, then it's possible the function board or main board inside the TV needs replacing. If the TV is not under warranty you can try just disconnecting the function board. This won't cause any problems as long as there is a separate IR board for the remote control. Of course if you disconnect the function board, you will not be able to use the controls on the TV.

If it's under warranty contact the retailer or the manufacturer to setup a service call.