Win8 the option to repair the computer at startup by pressing F8 is as follows:
On Win7 and earlier Windows systems, press SHIFT+F8 to enter advanced startup options, and Windows 7, which contains the repair computer option in the advanced startup options under Default installation, can enter Windows Recovery ( Windows RE) environment. If not, you can use CMD as an administrator under the system, type "REAGENTC//info", press ENTER to display some of the Windows RE information, and when the value "0" after the "Windows RE enabled" option is "," the Windows RE is disabled. After you have determined that Windows RE is disabled, type the "REAGENTC//enable" command line and press the "enter" key to re-enable Windows RE.
However, because Microsoft in order to improve the speed of Win8, boot fast too late to press F8, so Microsoft simply canceled F8 start "Advanced Startup Items" (in the WIN8-DP version of the Shift+f8 can be started, but the CP version is canceled), when the system occurs when problems will automatically start advanced startup options.
You can also manually enter the following ways:
1, Win key +i key, choose more computer settings.
2, in the "General" option, the last "Advanced Boot", select "Reboot" can be.
3, or in the normal selection restart, hold down the SHIFT key and then reboot.
4, after the reboot, found that "advanced startup" is also the Metro interface, select the "Troubleshooter."
5. Continue, select "Advanced Options".
6, here you can see the "Automatic repair."
7, start automatic repair.
8, select the account that needs to be repaired.
9, enter account password.
10, continue.