Firstly, check that the PS3 is plugged into properly both into the wall socket, as well as the actual PS3 itself. Remember to check that wall sockets are not switched off. There is a power switch on the rear of the PS3, ensure the switch is is in the on position.

If there is a red light on at the front of the PS3, simply tap the power button which is located beneath the disc slot to the right. The light should turn green.

If the lights are flashing yellow or flashing red, then it is likely that your PS3 has experienced a hardware failure. This will need professional servicing.