Solution
1. Please access bios by pressing F2 while the asus logo appears, switch to advanced tab and find a option named boot boost. Set it disabled.
2. Then restart the machine and press f9 to access the hidden partition.
3. If no avail, please send back or get the support discs from the local service center.
link:http://support.asus.com/ServiceCenter.aspx?SLanguage=en