Apple iMac (21.5 and 27-inch, Late 2009) - Manual (Page 55)

Chapter 4 Problem, Meet Solution 55
3 Double-click Install Mac OS X.
4 Follow the onscreen instructions.
Note: To restore Mac OS X on your computer to the original factory settings, click
Options in the “Select a Destination” pane of the Installer, and then select “Erase and
Install.” If you choose “Erase and Install,” you’ll see a message reminding you to use the
Applications Install DVD to reinstall the bundled applications that came with your
computer.
5 When the installation is complete, click Restart to restart your computer.
6 Follow the prompts in the Setup Assistant to set up your user account.
Installing Applications
If you reinstall Mac OS X on your computer and select the “Erase and Install” option,
you must reinstall the applications that came with your computer, such as the iLife
applications.
To install the applications that came with your computer:
1 Back up your important files.
2 Insert the Applications Install DVD that came with your computer.
3 Double-click Install Bundled Software.
4 Follow the onscreen instructions.
5 When the installation is complete, click Close.