Booting into repair mode gives you various options for diagnosing and troubleshooting issues with your Windows 8 computer. To do so, follow these simple steps:
On the Windows login screen, click the Power icon, then hold Shift and left-click Restart.
Click Troubleshoot once your computer boots back up.
Click Advanced options.
Click Startup Settings.
Click Restart.
Choose how you want to boot into Windows.