Why is the green light flashing on my PS3?

The PS3's power indicator blinks when you turn off the system to tell you it's shutting off. As you probably know, the blue light indicates that a disc is in the drive and the red light is when the PS3 is off and in standby mode.

A constant green blinking light could mean some problem occurred and it is taking longer than normal to shut off, if it doesn't turn off, hold the front power button down for 10 seconds to turn it off. You may then have to turn the PS3 on again with the same button as the PS button on the controller may not turn it back on.