PS3 beeps 3 times when plugged in then shuts down - no lights

A few weeks ago, mys PS3 started turning on by itself and wouldn't let me shut it down by holding the power button. After powering up by itself a few times, I unplugged it for a day.

I plugged it back in and must admit that I didn't pay much attention to what happened then in terms of lights or powering up. I left it for a few hours and came back to find my disc had been ejected. There were no lights on the console and it wouldn't let me turn it on.

Now when i plug in the power lead, it will sound like it's powering up, beep 3 times, then shut down. No lights show when this happens.

Looking online, it seems that people have had similar problems but with different reasons behind it (faulty power supply, motherboard issue, YLOD, control board).

I wonder if anyone has had this exact problem and knows how to fix it?

My console has always had difficulties ejecting discs (it usually takes a few attempts) which makes me think it could be something to do with the control board? But would that be a reason for the lack of lights?