To reinstall iCal:
1. Insert the Snow Leopard Installation disk into the computer.
2. The disk will appear on the desktop.
3. Double click on the "Optional Installs" folder.
4. Double click on the "Optional Installs.mpkg."
5. Click on (Continue) in Introduction.
6. Click on (Continue) in Software License Agreement.
7. Click on (Agree) to agree to the terms of the software license agreement.
8. Click on the disclosure arrow ▶ next to Applications.
9. Select (✓) iCal.
10. Click (Continue).
11. After iCal has been reinstalled, download and install the Mac OS X 10.6.8 Update Combo v1.1 to bring iCal up to the most recent version.