1 make sure tv or monitor is on and change source to proper input IE Hdmi 1 or 2 etc.
2 Ensure your ps3 is off but ready to be turned on. Fat ps3 has switch in back that need to be in on position.
3 hold power button for 5 to 6 seconds and let go after 2nd beep, it should come on with a beep and wait for 2nd beep.
4 this should reset your video, if display flickers then it should come up.
5 if it doesn't, try turning the power off then on again. Repeat steps 2 to 4 if it doesn't work.
If you keep trying and it doesn't work, then your unit might have to be repaired.