RCA Guide plus gold gemstar T.V

Question

while we were watching TV it went off on its own and wont come back on.the little light on the on_off button on the tv keeps flashing on and off but no sound or picture when it comes on     weve never had a problem with this before. Please tell me what I can do or check

  thanks Lonnie                                                                                                           When we are watching tv it cut's off on it's own. The power button stay's on but no picture and no sound.