When you try to open the iLife '05 installer on the iLife '05 Install CD, you may see an alert that says the computer contains a DVD drive, and that you must install iLife from the install DVD.
If you know you have a CD-ROM drive, then just click Continue. If you're not sure what drive you have, you can check Apple System Profiler or you can just try putting the DVD disc in. If it automatically ejects after a moment, then you don't have a DVD-ROM drive and you should use the CD to install and click Continue if the alert appears again.
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