Thanks for reply.
First i disengaged lcd from the board and i found boards code.
The code is "MP-783W TSLS v 1.1 2006.05.31"
And i dont know that how can i update firmware bacause i tried a few mp3 player utility but none of them recognized it.
so if you find a firmware for me and tell me that how can i fix this problem, i would be happy.
Good days.