How to use the Mac OS X 10.5 Leopard Time Machine feature to restore your Mac to a previous state.
1. Insert the OS X 10.5 Leopard disc into the drive.
2. Launch Install Mac OS X.
3. Select Utilities > Restore System From Backup. When prompted click Continue.
4. Select the drive where your Time Machine backups are stored.
5. Select the backup you wish to revert back to.
6. Follow the wizard through the rest of the restore process.