PS3 slim comes on and then right back off

I recently got a PS3 slim 320 gb used, I hooked it up with the AV cables and it worked 3 or for times, then we plugged it up, turned it on later and the red light will change to the green light, the fan comes on for a second then the whole console shuts down, Nothing at all shows on the tv screen and their is no sound at all. Everything is hooked up correctly and the tv is set to the proper channel, I have checked all of that numerous times. I have tryed resetting the console according to the info I have found on the net, still nothing. Anyone know what to do, other than buy a new console? I am an amature small electronics repair/tinkerer! Please help!