Hi Moohammad,
Do you receive any error message?
Follow the methods below:
Method 1: Try to perform a system file checker (SFC) scan.
System File Checker Tool will try to help you in fixing all the corrupted files and folders in the computer.
a. Type “cmd” on the Start screen.
b. Right-click on it and select “Run as administrator”.
c. Type the following command and press Enter:
sfc /scannow
Method 2: If the issue still persist then try to perform a refresh on your computer.
How to restore, refresh, or reset your PC
http://windows.microsoft.com/en-in/windows-8/restore-refresh-reset-pc
Note: The Refresh will uninstall and reinstall all the apps downloaded from the Windows Store. But any app downloaded from external sources will be removed.
Note: You will need to reinstall Windows 8.1 again.
Do get back to us and let us know the status of the issue by your next post or in case you need further assistance. We, at Microsoft strive towards excellence.