What to do when some of the system files are corrupted? Back to the old days, I had to run a Windows in-place upgrade to replace them with the original ones from the installation disc, and had to install all the updates afterwards. But since Windows Vista, there is a much better way repairing the corrupted system files.
sfc, System File Checker, is a command line utility in Windows that allows users to scan for corruptions in Windows system files and restore corrupted files. If any corrupt or missing system files are found, they will be replaced automatically using cached copies kept by Windows for just that purpose. The process can take a while to finish.
You will need to run the command prompt with administrator privileges and enter the following command to start the scan and repair process.
sfc /scannow
The sfc /scannow command will scan all protected system files, and replace corrupted files with a cached copy that is located in a compressed folder at %WinDir%\System32\dllcache.
Next time when you see your Windows is acting up, fire up a Command Prompt as Administrator and run this command to see if there are any corrupted system files that occurs.