You should be able to install your game from the Backup CD by completing the following instructions.
1. Insert the CD.
2. You may receive an autorun prompt with a button to install your game. If you do, click "Install" and proceed, affirming the prompts as they occur. If you do not receive an auto prompt, complete the following...
Click your "Start" button (located in the lower left hand corner of your screen.
Click "My Computer."
Click on the icon associated with the CD drive. The autorun should start. Follow the prompts and you should be set!
If you encounter problems reinstalling from older Backup CDs, just try reinstalling directly from the iWin website as there maybe an update to the game.