My sons PS3 has started crashing when playing games. It starts off fine when the console is first switched on from cold but after a few minutes the screen starts to flicker, gradually worsening until the game finally freezes. I initially thought it was the laser but blue ray movies and DVD's play ok. I suspected that maybe the HDD was failing but I don't know if it is in use when playing movies. Can anyone please shed any light on this problem and how I might resolve it.