ICal

I'm having a problem opening the ICal program...I recently bought an intel machine and imported all my "stuff" from my IMac. A couple of small hitches, nothing too disastrous, but since I can't open my ICal..neither on my new intel nor on my Imac. If I want to reinstall the ICal from the installation disc what's the best way, is it found under the Mac OS and Applications or under just Applications?