NEC FS 5195 work for awhile then drop into standby then will not turn on

I have a NEC FS 5195 51cm stereo tv it stays in standby mode it belong to my mother she was watching it and it just shut down into standby mode and would not turn back on anyway she has been after me for about amonth to fix it and finaly dropped it over this weekend so I plugged it in and away it went all ran well for a few hours. It could play the games on it watch tv turn in on and off to standby mode then turn it on with no problems after a few hour I was playing one of the games on the tv after watching abit of tv then it just went into stand by mode and now it will not turn back on any ideas would be most appreciated. Best Regards Danny