If your F8Sg notebook computer is with the pre-installed Vista, you can use the hidden partition, reserved for recovery purpose, in the hard disk to restore your computer to the factory settings. Backup your personal data first.
Restart your computer. Press F9 key immediately when the ASUS logo appears. This will start the recovery procedure, including the installation of all the drivers and utilities. Follow the instructions. Your computer will be restored to the factory settings.