An error message like this may have just come up on your ps3: "The copyright protection information is invalid (80029513)".
The are a few reasons this might pop up. Maybe you've been sent a new PS3 because your old one broke (check the bottom of the message for this) or you have just created a new user account with a new online ID and deleted your old account.
The latter situation is a problem, you may have transferred all your save games over and all the old games you had are still visible (e.g. downloaded PS1 games or PSN games) but you will not be able to play on them (even game discs where you have downloaded add ons for those games.) The main reason is that you can only play those games with the account that you bought those games with being active and on your system. Your download list is also attached to accounts - so with your new account you don't have the download list that you had before (you can get it back though with your old account). All this is to stop poeple using your account on other PS3 systems and getting games for free.
To solve this problem you will need to create your old account again. Create a new user and call him what you want (Say Friends - you'll see why I call it this later). Log on with this new user and go to "PLAYSTATION network" and select "Sign Up for PLAYSTATION Network" then select "No,I will use an existing account" type in the email you had with your old account and the password and it should automatically come up with the menu screen again and be signed in with your old account.
There is still more to do - you will still not be able to play your old games. First of all go to "PLAYSTATION Network" and select "Account Management" then select "Account Management" and then select "Activate System" select "PLAYSTATION 3 (This System)" select "Game Content" and if it says "This system is currently: ACTIVE" then you are fine and you can click cancel if not just select "activate system". Basically just want your system activated.
Finally to get your games back -go to the PLAYSTATION store and select "View Downloads" at the top of the screen (you can also do all the following in the "Transaction Management" part of the "Account Management" screen). You will need to select each game on the list which is currently installed on your system (including add ons - everything installed on your system) and as soon as the message "Activating please wait" has disappeared and it starts downloading cancel the download by pressing the o button on your controller.
Once this has been done for every game you should be able to play them all - there is no need to download all the games fully, you just need to activate them again. IMPORTANT: bear in mind that you may only activate games 5 times on your system before you cannot activate them and play them anymore.
Now you need to keep the account you just put back on your system because this holds all your old downloads and games. However with your old account back on your PS3 and activated you can play the games on the new account with the new user you created (just make sure you never delete your old account again). I call the old account the friends account so that when friends come over the save games on my new account won't be ruined.
So there you are you can now still be called BIGDADDY6969ohyeahhhh and play your old games.
For people who have had there system replaced - deactivate and reactivate your system as described above and active each of the games as described above - all your games should then work.