I've had Assassin's Creed on my system (purchased from the PSN Store) for over a year now, and just recently got PS+. I was able to play the game for about 2-3 days after getting PS+, and now today, it says the game is expired? I had purchased a one year subscription, so it can't be because of PS+.
The weirdest part about it, the information on AC says it was created today at 4:15am and expired today at 5:15am or something like that. Did my game corrupt or something? Did PS+ screw it up? I'm definitely not willing to pay another $20 for the game after I had just paid $50 for PS+, like the PSN is suggesting I do. Is there some option I need to go to?
Oh, and another one. I had purchased the full version of Battlefield 1943 a while ago, and now it's bumped down to the trial version. Seriously, **bleep** is going on with my account?
Subscribing to PS+ doesn't do anything to the installed games on your PS3, or affect the expiration dates of any of your games one way or the other. License files for games and add-ons that are paid for in the Playstation Store have no expiration date. License files for games and add-ons that are downloaded free as Playstation Plus benefits expire about a day after the Playstation Plus subscription expires. Even if you renew your Playstation Plus subscription, your Plus content will still expire; but you can renew the license by finding the content in the Playstation Store, and clicking the Download button. The software won't actually be downloaded again. The license file will just be replaced. If you have a game that you installed expire, then just find it in the Playstation Store, and click the Download button to renew the license. You will only have a problem if the content is no longer marked as purchased in the Playstation Store.
If you delete the user profile for the user whose PSN account purchased a game, then the game will no longer work. The only way to make the game work again is to create another user, sign up for PSN with the PSN account that purchased the game, and then start the game under that user. That will download a new license.