You have several threads with very different issues.
The last one I answered mentioned that you upgraded from Windows 8.1 to Windows 10, then made an image of your system, then reverted back to Windows 8.1. . .??
I honestly don't know what has happened to your system with all this upgrading and degrading (reversion).
To run chkdsk, type chkdsk /r into a CMD screen, then re-boot.
If that does not work, my guess is that your current OS is corrupted in some manner and you should be looking to reinstall Windows 8.1 using your recover media (DVD or USB - whichever you created when the system was new, assuming that you did so).