It looks like one of your buttons is stuck, that may be mechanically or electrically. If you still have warranty I'd go with that.
If you don't have warranty you could open her up and look if you can see something obvious going wrong, clean the board with isopropyl, close her up and hope for the best.
The microswitches require a fine soldering tip, a very steady hand and a lot of patience to replace, if you're not familiar with hand-SMD-soldering you can pretty much forget about doing that by yourself.