Why you dont post the whole story? I think it will be informative for all of us they dont know this.
Well, i had some major problems w/my PS3 recently locking up and not playing any games/movies. After calling Customer Support, they suggested that i do a hard reset. This did seem to solve my problems, so here is the procedure per Sony CS. I would consider this a last resort troubleshooting procedure.
Be sure to backup your settings/games saves by doing a System > Backup on your PS3 or you may lose your game saves! Also, this is a last resort procedure prior to exchanging/returning to sony.
I had trouble with the video settings on mine and I just powered off and hooked up through the AV cable instead of the HDMI cable then swithed off and swapped backt o HDMI and the screen came back. I think if it detecs a display connected in a different way to how it is configured it is smart enough to switch. That was with Firmware 2.40.
Thanks for posting the reset trick though will have to file in my memory banks.