Grobanish
I know it's on, and I looked up on google about this problem. People have said that you're supposed to hold down the ps3 button until it beeps three times. I've done this, it beeps three times, then it just turns off. Nothing else happens.
Holding the power button when it's on
forcibly turns it off. This is generally not a problem.
When you hold the power button until it beeps
when it's off, it will turn the PS3 on and
reset system settings (like display, sound, network, etc.)
If you can't see anything when you turn it on, wait until it's finished booting, then shut it off. Then turn it on by holding the button, and wait for it to beep. It will reset its configuration and try to auto-detect your setup. You will need to reconfigure it.
If you still can't see it, check your cables, and try a different hookup - if your TV has component inputs (red, green, blue cables), try that. Otherwise, try S-video (4-pin black cable) or composite (yellow). If you still can't get anything, call Sony and order a repair.