Its apparent you don't know what you are doing,and if you had taken the time to locate the user manual you wouldn't have this dilemma.
I have no sympathy for people without common sense.
You are lucky to be here posting this question.
you discription was clearly not thought through before you started tapping those keys.
your grammer is appalling!!!
get yourself that manual!!!
I can tell you the two alphabetical flashing letters relate to your inability to replace the damm it COVER.
Maybe you have damaged the tamper hardware.
maybe you couldn't be bothered to replace or tighten the top right hand screw........who knows your the man with the screwdriver.
no name, February 2012