In this section I will show you how to use the MS-DOS Prompt (or CLI: Command Line Interface as it used to be called) to scan Windows 10 system files for problems. MS-DOS (Microsoft Disk Operating System) was the programming language used to operate a computer, back in the 1980s and 1990s, before Graphically User Interfaces (GUIs or Windows to you and me) replaced it.....but not completely. Forget the technicals though. In todays age it is only used, if at all, in rare cases such as fixing the operating system called Windows 10.
In this example I am going to show you how to use the DOS Command sfc and more precisely sfc /scannow which tells DOS to check Windows 10 for file corruptions and so on. In order run (execute) a DOS Command you first need the DOS Prompt (DOS Window) open which is done by double clicking on its desktop Shortcut Icon - The desktop shortcut icon you are now going to create!
First you need to locate the executable file called cmd.exe, which lives inside the SYSTEM32 folder. So you need to double click on the THIS PC folder first and then on the C:\ Hard Drive. From there, double click on the WINDOWS folder and then on the SYSTEM32 folder. Now you are inside the SYSTEM32 folder locate the execute file called cmd.exe. Right click on it, to bring up its context menu (Options menu), and then select the DESKTOP (CREATE SHORTCUT) sub-menu menu-item to place a shortcut icon on the desktop.
Fig 1.0 Inside the SYSTEM32 folder - Right click on the cmd.exe file to create a Shortcut Icon on the desktop
Fig 1.1 The shortcut icon has been created on the desktop
With the shortcut icon created, on the desktop as cmd.exe, you may then want to rename it for the sake of knowing what it is (i.e. rename it Command, DOS or whatever; if you want to). In this example I have renamed it to DOS. Anyway! From there you need to right click over that shortcut icon and select the RUN AS ADMINISTRATOR menu-item in order to bring up the actual DOS Window (Command Line Interface). It is from this DOS Window that you execute a DOS Command.
Fig 1.2 Right click on the desktop shortcut icon and select the RUN AS ADMINISTRATOR menu-item to continue
After clicking on the RUN AS ADMINISTRATOR menu-item a UAC (User Account Control) system requester will appear whereby you then need to click on its YES button to continue.
Fig 1.3 Click on the UAC system requester's YES button to continue
User Account Control (UAC) is a feature of Windows 10 that helps to prevent unauthorized changes to the computer, such as deleting a system file or installing software. When attempting to launch the DOS program the UAC security requester above automatically blocks you off, because it wants to know if you are the one attempting to launch the DOS program and not a robotic piece of malicious software for example. In the above case simply click on the YES button to continue, or on the NO button to cancel the DOS session.
When the DOS Window appears type the following DOS Command into it - sfc /scannow - and then press the ENTER keyboard key. This will execute that dos command which will then scan the Windows 10 system files for corruption. System files that relate to Windows 10 starting properly and running properly. Hence the reason for showing you this dos command. It is useful when Windows 10 is playing about, showing you system errors, programs not working correctly and so on.
Fig 1.4 Type in the DOS Command: sfc /scannow and then press the ENTER keyboard key to continue
Fig 1.5 17% of the system files scan has been carried out - Hopefully no file corruption yet!
Fig 1.6 The system files have been scanned for corruption - No file corruption found
The above scan results show that my computer has no file corruption on its system files. However, you have to take those results with a pinch of salt (Rock Salt or Table Salt, your choice!). Meaning: You may of had noticeable problems on your computer before the scan and no problems after the scan, which means the scan was successful at clearing up those noticeable problems even though the sfc dos command reported no problems (Integrity Violations) found.
A good time to use sfc /scannow is when Windows Update for example has just messed up Windows 10, for whatever reason(s) - Normally due to Windows Update wrongly guessing which updates Windows 10 needs and/or which software drivers need updating for a particular piece of hardware thereby giving Windows 10 incompatibility issues/problems it might not of had before the updates. Yes, even Microsoft makes mistakes!
Below is an example of file corruption, found using the sfc /scannow command, which would need repairing in Safe Mode with the dos prompt option using the same sfc /scannow command. Here is an article on this particular Windows Resource Protection file corruption problem: Windows Resource Protection found corrupt files but was unable to fix some of them.
Fig 1.7 The system files have been scanned for corruption - Corrupt files found!
There are plenty of DOS Commands for Windows 10 that relate to shutting down Windows, Formatting a disc, Renaming a folder, Scanning a disc and so on. Most of which are carried out by Windows 10 and more precisely by its Menus and Buttons (GUI: Graphical User Interface), therefore making DOS Commands redundant for most users (which is a good thing as DOS Commands are quite powerful in the right/wrong hands). However, if you are interested in DOS Commands search the internet for "DOS Commands" or "Command-Line Reference" for example. Here is an example DOS Commands website - Scroll down its page slightly or click on the ALL MS-DOS COMMANDS link.
You can customise the DOS Prompt window by right clicking on its title bar and selecting the PROPRTIES menu-item. You can change the font size, window size, editing and so on.
Fig 1.8 Right click on the DOS Prompt's title bar and select the PROPRTIES menu-item
Fig 1.9 Customise the DOS Prompt window
Fig 1.10 The DOS Prompt has a new font size, background colour and foreground colour