Sometimes you may need/want to repair Windows itself,  or sometimes an error may pop up for missing DLL files - due to the proprietary nature of the Windows OS, **you cannot download these files from a website on the internet. Any attempt to do so will likely be malware.**  Instead, run the following commands as admin to repair missing Windows DLLs and other error codes/issues.   "SFC /scannow" can be used offline and on Windows PCs prior to Windows 8.   DISM is an online (internet connection needed) tool that compares your copy of Windows against a known good copy on Microsoft servers and replaces files and repairs it as needed.   Use the following commands in order:  "DISM /Online /Cleanup-Image /CheckHealth"  "DISM /Online /Cleanup-Image /ScanHealth"  "DISM /Online /Cleanup-Image /RestoreHealth #cmd #windows #OS