That's a bit of a weird one. I did pretty much the same thing when I plugged the PS3 into the SDTV I couldn't figure out why it didn't display, then... shock horror ... the PS3 instruction manual actually had some useful info about how to go back to std AV output from HDMI I didn't even need to do the Google.

When I went back home I had no problem getting HDMI going again. Though I do seem to recall having to plug in both AV and HDMI to change display back to HDMI manually. But it worked first time.

Something wrong with your HDMI cable perhaps? Unusual for a new cable to be busted but it does happen.

HD is soooo sweet compared to SD. Bummer that you're missing out.

a $40 cable ? good thing mine is ~$10 and is still going strong after 3 years

Yea seriously, $40 for a cable like that is just a waste. Monoprice/Amazon/Newegg!

Glad to hear that the cable was the OP's problem.

I have never had a problem, I use HDMI, but sometimes you have to hold down the power button for more like 10 plus sec, Its not that its not working , the PS3 is just pushing out the signal to a different place, try a few different ways of resetting the PS3 with holding down the power button, that will always work, some PS3 take longer then others.