Hi,

Did you use a DVD or Bootable USB to install windows 8.1?

I would suggest you to follow the troubleshooting steps and check if it helps;

Method 1: Perform an Automatic repair using Windows 8 bootable DVD or USB drive and check if that helps.

Follow these steps to perform Automatic repair

a) Insert the installation DVD or USB and boot Windows 8 from it.

b) In the ‘Windows setup’ page select the ‘Language to install’, ‘Time and currency format’ and the ‘keyboard or input method’ and click on ‘next’ .

c) Click on ‘Repair your computer’ and select ‘Troubleshoot’ .

d) Click on ‘Advanced options’ and select ‘Automatic Repair’ and select the operating system.

Method 2: I would suggest you to Use the Windows Recovery Environment (WinRE) to run System Restore.

a) Insert the Windows 8 installation disc into the disc drive, and then start the computer.

b) Press a key when the message indicating"Press any key to boot from USB or DVD ….” appears.

c) Select a language, a time and currency, and a keyboard or input method, and then click ‘Next’.

d) Click Repair your computer.

e) In the System Recovery Options dialog box, choose the drive of your Windows installation and click ‘Next’

f) At the System Recovery OptionsDialog Box, click on ‘System Restore’.

g) Follow the System Restore Wizard instruction as usual and choose the appropriate restore point.

h) Click ‘Finish’ to restore the system.