How can I enter [Safe Mode] when I can't enter the system of Windows 8?
From Windows 8, you will not able to enter [Safe Mode] by pressing "F8" when you boot the system.
There are two methods to enter [Safe Mode].
You can find how to enter [Safe Mode] while you can't enter the system.
If you can enter the system, you can find the method from the other FAQ as below.
Windows 8 - How to enter [Safe Mode]?
If you can't enter the system, the system will enter [Automatic Repair] mode.
If "Automatic Repair" couldn't repair your PC, please click [Advanced options].
Click "Advanced options".
Click "Startup Settings".
Enter the proper mode by using the numeric key or function key F1~F9.
You can enter [Safe Mode] from the 3 options.
(4) Enable Safe Mode
(5) Enable Safe Mode with Networking
(6) Enable Safe Mode with Command Prompt
If you select (4)Enable Safe Mode, you will see the display below.
Now, you can install an external storage and back up the important files to the storage.
Then you can refer to the FAQ : If I can't enter the system, how can I restore the Windows 8 laptop or PC to factory default settings?
Finally, if you have any issue about the operation process, please consult with the ASUS Service Center.