Here are two simple troubleshooting steps to try if your Windows installation has been corrupted or is not functioning properly. These commands work in Windows 8 and Windows 10.

%windir%\system32\sfc.exe /scannow

This command used with SFC.exe is a tool that will scan your system files for corruption and replace them with a cached version if necessary.

%windir%\system32\DISM.exe /Online /Cleanup-image /Restorehealth

This command using DISM.exe will scan your file system for inconsistencies and repair them if possible using Windows Update as a source for binaries. This is a modern version of the System Update Readiness Tool that was available as an update in Windows 7.