Hi,
Thank you for posting the query in Microsoft community!
I can imagine the inconvenience you have experienced. I will definitely help you in fixing the issue.
Did you make any changes on the computer prior to the issue?
**Method 1:**Disconnect all the external devices (printers, scanner, USB (universal serial bus) drives, etc...) Except mouse and the keyboard and then boot up. If this corrects the issue then add the devices back one at a time until you discover the piece of hardware causing the issue. Then get any updated drivers\software for the device.
Method 2:
I would suggest you to perform a startup repair using Windows 8 bootable DVD or USB drive and check if that helps.
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 3:
If the issue persists then you may perform a refresh of the Operating System,
Refer the steps for the same-
a) Boot with the Windows 8 DVD and then select “Next”.
b) Now, select “Repair” and then select “Refresh your PC”.
You may refer the article for detailed information about a Refresh-
How to restore, refresh, or reset your PC
http://windows.microsoft.com/en-US/windows-8/restore-refresh-reset-pc
If you are still facing the issue, please reply and we will be glad to help you.