PS3 Restarts After Quiting Game?

Whenever I quit the game using the PS button it beeps and restarts. I just got it and it does this when playing LittleBigPlanet. I have seen on many other threads on the internet that many people have been experiencing this problem using LBP too. How can I fix this problem? Also, is this a problem with the system or the game? Thanks. (I only have LBP. My PS3 is new so I can’t try other games until I buy more). Thanks.