Had my Nano M3 2 years but only just set up for continuous use. Current Release 5.3.037. Will boot-up from main switch and for a while is OK. From stand-by will open but does not then respond to remote i.e., change channels, operate menu, shut down etc. etc. Sometimes will open with small picture but again unresponsive. I've reset EPG settings from an earlier thread, tried to flash Release 6.2.10 from HDD but receive error message. Any thoughts please?