I've had my ps3 for a while now, but hardly play it. When I do, it's only for a 1-2 hours at most & I never play blurays on it. Recently, I've had this small issue that when I'm done playing I just power it down, either using the ps3 remote or on the on/off button on the ps3 unit. The unit turns off normally, but comes on unexpectedly by itself, so now I just turn off the unit completely. What seems to be causing this??