Snow Leopard seems to be a little different to its predecessors when it comes to performing a clean installation/re-installation. The following needs to be done:
- Boot off the OS X install DVD – place DVD in drive, restart Mac, hold down C when it “bongs” and keep it held until you see the Apple logo with a spinning wheel
- Click Continue when you see Welcome to OS X Snow Leopard
- Choose Utilities and then Disk Utility
- In Disk Utility click on your hard drive on the left, choose Erase and go with the defaults (OS X Extended (Journaled))
- Once the drive has been erased select Quit from the Disk Utility menu
- Back in the install screen click Continue
- Choose your newly erased hard drive, agree to the license and click Install
- The installation process should now run for about 30 minutes
- After that you’ll have to fill in your personal info, location details, network/wireless info, etc.
Hope this helps!