"Players trying to launch Tron: Evolution are now met with a message telling them that the 'serial key has expired'. This applies to the retail version as well as the Steam version which is delisted from the store. Players who previously bought the game from Steam cannot play the game, and are met with these messages:
The cause of this problem appears to be Disney not renewing their 'subscription' to the SecuROM activation system for this game. This means that even existing owners of the delisted game cannot play it for the foreseeable future."
More at the link.