PS3 HDMI output problem

[mainman]

Today, I got my first Blu-ray movies in my mail.

I tried out 'Enter the Dragon' on my PS3. Wasnt planning on watching it, just to try it out, and make sure, the BD wasnt region locked (I'm European).

I was in the menu of Enter the Dragon, and I pressed the square button (just to find out what it does). All of a sudden, the screen went black, and didnt come back.

I tried restarting my PS3, didnt work.

I reset my PS3, i had picture over the regular standard cable, after the reset. I then went in the menu and selected HDMI. But after selecting HDMI, it just went black, I still had no picture over HDMI.

I looked at the cable itself, to see if it wasnt connected properly, it looked fine.
I reset it again to start over, still didnt work. I tried calling Sony, but they were closed for the day.

After about a half an hour, I went in the menu again to select HDMI, and this time it did work.

I dunno what it was, have you guys ever had such a problem?
And after reading this, what do you guys think, might have caused this problem?

I got my PS3 for about 2 or 3 weeks. I dont have any PS3 games, and havent watched any Blu-ray movies with it. So I havent given it a proper work-out yet.

I'm a bit worried, and I just hope this problem wont occur again.
What do you guys recommend me doing? Call Sony and change my PS3 with a new one?

Thanks