I had the same problem. http://answers.ea.com/t5/The-Sims-3/Sent-a-Sim-to-University-unable-to-select-a-house-and-play/m-p/1...
Try starting a new game while not logged in. If that doesn't help, do a factory reset ( http://answers.ea.com/t5/The-Sims-3/FAQ-Troubleshooting-Steps/td-p/714 ) then try starting a new game while not logged in.
I tried the factory reset and playing not logged in but that didn't work. I have now unistalled everything and only reinstalled the base game and am still getting the same problem.
So the tick staying grey continues even if you remove all user files and NOT putting them back for the moment ?
(just making sure I understand right)
I completely unistalled all the games and deleted the files to start from scratch. Reinstalled only the base game let it patch and update. Loaded up fine and starting a game through CAS worked fine but when I started a new game and clicked choose a household it stopped at the greyed out tick.
