Open a command prompt with admin rights and run this DISM command to detect and repair corrupted files on the HDD:
This is the advanced version of sfc /scannow. Windows now downlaods the corrupted files from the Internet instead of telling you that the files can't be repaired.
This is a windows of command.com:
"Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.
Beginning system scan. This process will take some time.
Beginning verification phase of system scan.
Verification 100% complete.
Windows Resource Protection found corrupt files but was unable to fix some
of them. Details are included in the CBS.Log windir\Logs\CBS\CBS.log. For
example C:\Windows\Logs\CBS\CBS.log. Note that logging is currently not
supported in offline servicing scenarios.
C:\Windows\system32>DISM /Online /Cleanup-Image /RestoreHealth
Deployment Image Servicing and Management tool
Image Version: 6.3.9600.17031
The restore operation completed successfully. The component store corruption was
The operation completed successfully.