Found this on another site, from personal experience but its very well written so here you go.
The Playstation 2 is not only a video game system, but also a DVD player
as well. In many families, the Playstation 2 serves as the "kids" DVD
player, which means that many parents choose to take advantage of the
parental lock feature to limit what kinds of movies the Playstation 2
will play back.
There could be instances where you entered in a parental code months
ago, and now can't remember it. Or, you may have purchased a used
Playstation 2, and you never knew the code to begin with. If you or the
prior owner set a parental lock code, the Playstation 2 won't play back
many movies without entering the code first. You could try to hunt down
the original owners, or start inputting every code possible starting
with 0000, but it's easier to reset the password and disable parental
lock using a secret code.
Here is the procedure to reset the parental lock code:
A note for parents:
- Bring up a screen where the unit asks you to enter in the parental code. You can either insert a restricted disc, or enter the DVD setup menu and go to "parental control" under custom setup.
- When the screen asks for the code, press the SELECT button, then enter in the code "7444".
- The level adjustment under Parental Control
dictates the strictness of the player. The lower the value, the more
strict it will be. Either increase the value to lower the restriction,
or disable the lock entirely by setting it to "off".
- Once you have made your adjustments, be sure that the DVD tray is
empty, and press the RESET button on the front of the Playstation 2. It
is imperative the tray is clear of any DVD or game for the unit to save your settings.
If you're wondering what is
stopping your child from using the above procedure to circumvent your
rules, you can verify that they haven't reset the parental control very
easily. Since the above procedure eliminates the old password entirely,
all you need to do is see if your original password still works. If it
does, they did not use the above procedure to break the rules. If it
doesn't, they might be trying to pull the wool over your eyes.
Please rate accordingly