Inside Windows OS there is one built in command-line tool called 'SFC' to check and repair all protected system files. SFC scans the integrity of all protected system files and replaces incorrect version.
Example on command prompt type "c:\>sfc /scannow" to verify and repair all protected systemfiles .
/SCANNOW - Scans integrity of all protected system files and repairs files with problems when possible.
/VERIFYONLY - Scans integrity of all protected system files. No repair operation is performed.
/SCANFILE - Scans integrity of the referenced file, repairs file if problemsare identified. Specify full path
/VERIFYFILE - Verifies the integrity of the file with full path
/OFFBOOTDIR - For offline repair specify the location of the offline boot directory
/OFFWINDIR - For offline repair specify the location of the offline windows directory