Archive and Install
If you've been having problems with your computer and you're installing Tiger as a way to start over, reformat your hard drive before beginning the installation process. If you don't want to part with your old system files, during the Tiger install click "Options" and choose "Archive and Install." This type of installation renames your old system folder and installs the new system in a separate folder on your computer. The drawback is that you'll end up with 4GB–5GB of duplicate system files that might end up conflicting with the new files, forcing you to reinstall some third-party software or reconfigure lots of esoteric settings.