Figured I'd add helpful tip based on my recent experience.
I turned on the PS3, which is connected to the HDTV with an HDMI connection, and there was no video/audio. I looking in various places an the 1st step was to hold down the on button to restart. That did not resolve my issue. I swapped out the HDMI cable and still was a no-go. Advice varied greatly on how to proceed from there.
I solved the issue by getting out the old RCA type audio/video connector and hooked up the PS3 using that IN ADDITION to HDMI cable. I switched the TV to the RCA type input and I was prompted with a message that stated "The PS3 also has an HDMI connection, do you want to use HDMI instead". If you select that, you can then switch the TV to the HDMI input and you are then prompted with a count down screen(to reset back to RCA) which requires you to accept that you in fact do want to use this HDMI input.
Boom, problem solved. It does not makes sense to me why you have to do that, considering the HDMI was the only active connection. But that is what I have to do to fix my PS3 HDMI connection. I've had to do this twice now in the last three months. I'm not sure if this is an indication that my machine is on it's way out. But I'll keep on doing this when the issue comes up.
Hopefully this was helpful to someone else who faced the dearth of info I found out there when researching the problem.