Teach you to find the Safe mode of F8 under the Win8

In Win8 we will not be able to press the F8 key to enter Safe mode under Boot, which is limited by the WIN8 new security boot mechanism. If you want to enter Safe mode by pressing the F8 key at power-on, you can do so by following these steps.

How to retrieve the Safe mode under F8 in WIN8: Start a command prompt as an administrator

In the Open Command Prompt window, enter

Bcdedit/set {default} Bootmenupolicy legacy

Carriage return is determined. Restart your computer after you perform this action to see the traditional advanced startup options by pressing the F8 key

If you want to return to the Windows 8 default boot mode, you can do so by entering the following command.

Bcdedit/set {default} bootmenupolicy standard