I've done a Google and forum search on this, and all I've come up with is it may be a Windows 8 issue.

Basically I started up the Sims 3 Pets game, for the first time on my new computer, and when I go into the main game options to adjust aging/free will/etc everything's frozen or locked. I can't move the slider bars. I can't adjust anything.

Can anyone help? I don't want to play with the game's default settings. Thanks.

Edit: For anyone else who may come across this, once I went into a town and looked around the game options unfroze. You just can't adjust them at the very beginning.

This is happening to me right now actually. I'll try what you suggested in your edit.