Back-up any data you need to keep.
1. Insert the grey install DVD and restart the iMac.
2. Hold down the C key during start up.
3. Do an "Erase and Install".
This will clear everything off and leave you with a factory feel to the iMac.
(If you had banking data on there, and for example, would be concerned if you son has housemates that may have access to the computer, you use can use Apple Disk Utility on the Install Disk (select from either the Menu Bar or options buttons (dependent on OS X version)) and choose to erase the drive and Zero all Data. This takes some time but will mean that the data cannot be easily recovered. On Panther/Tiger install disk you can 7-way write random data - which is more at the erasing-government-secrets type level of security.)
I'm about to give my iMac to my Son and want to do the same thing. I have a related question about the rebuild once the startup disk is erased.
Is there any way to start off at a higher revision of Tiger than the first release or must you install that and go through the agony of downloading all the updates stage by stage?
No not really. The version on the disk is the version that is installed.
To avoid re-downloading updates in the future rather than using Apple's Software Update you can download the 10.2.8, 10.3.9 or 10.4.8 'combo' update this will take you from 10.2, 10.3 or 10.4 up to the latest version. You can burn this combo update to CD for re-application later without the need to download. Downloading the Combo will also allow you to update numerous Macs with a single download. The transition to Intel does complicate this somewhat as the Intel and PPC combos are different.
The retail version of Tiger I bought was 10.4.3; you may find yours is an older or newer version. Either way you have a 149Mb download to do.
Hello Ian - Its the other Ian B here
To add to Adam's always excellent words...
If you are concerend about the time taken to down load a whopping 150MB of data, you could always take a blank CD and a large smile to your local Apple dealer / store and ask them. It has worked many times in the past!
Is there any way to start off at a higher revision of
Tiger than the first release or must you install that
and go through the agony of downloading all the
updates stage by stage?
If you are doing a clean install of Tiger, Software Update will update you from 10.4 to 10.4.8 in one step after the initial install is complete. You don't need to update one version at a time. Of course if you are on dial-up, I'd take the earlier suggestion and try to get a copy of the combo updater on CD first.