Sims 3 Showtime and generations problem

So i have the EPs pets, ambitions (downloaded from origin), late night (downloaded from origin), showtime, and generations. I wanted to play my game but it said I had to have the showtime disk in to play. normally I could've used any sims 3 disc. I can't find my showtime disk so I want to know if there is a way I can fix it. It won't let me play the games I purchased and dowloaded from the origin website but they are installed. I tried uninstalling and then re-installing my generations ep but i couldn't re-install since I lost the serial code. I registered the game so is there a way I can re-install it withought the paper that said the serial code? also, can I get a serial code to register my games and get the simpoints from the EPs i bought from origin? I know its a lot but please help.