How to Reinstall Windows 10 on a Device already running Windows 10

Sometimes, mostly in the case of potential security breaches, it is useful to reinstall Windows on a device that is already running it to create a "Clean Slate" for your operating system

Prerequisites: Must have a USB device with the Windows 10 ISO tool installed

Difficulty Level: Member • Nerd • Platypus

Estimated Time: Varies depending on hardware of device; 15-45 minutes

Expected Outcome: Windows 10 will be reinstalled, with or without files saved (depending on the decided process)

Tools Required: If you need to create the Media Creation Tool, an empty (formatted) USB drive that is at least 16GB, device running Windows 10, power source (charger for a laptop, plugged in for a desktop)

Steps to Perform 

1. Make sure you have the Microsoft Installation software for Windows 10 installed on the USB flash drive
   
   1. If you do not, go to https://www.microsoft.com/en-us/software-download/windows10 and select "Download Tool Now" under the "Create Windows 10 Installation Media" section
   2. Once downloaded, run the executable by double clicking "MediaCreationToolxxHx" (the x's represent version numbers of the downloaded ISO)
   3. Make sure to allow admin access, accept the terms and conditions, and then select "Create installation media for another PC"
   4. Then select the removable device (your USB) that you would like to make the installation media
2. Once you've double checked that you have a media creation tool for Windows 10, insert it into the device which needs Windows 10 reinstalled
3. Once you open the device's files, find and run (double click) the application named "setup"
   
   1. This should be the bottom most of the files on the device
      
4. Allow admin access for the application via an on-screen prompt and follow the steps on the window
5. Agree to the terms and conditions once more
6. Decide what to keep, the default is always to keep personal files, but this can be changed by selecting the option "Choose What to Keep" before finishing this installation
   1. Option 1: Keep personal Files - This option will keep any documents on the device and only change the Windows 10 specific files. It is best used when there seems to be a slight hardware issue that a fresh Windows install may help, such as slow load times, unusually high hardware usage, and other similar issues
   2. Option 2: Remove personal Files - This option is the "Scorched Earth" of installing Windows, and is also often referred to as a "Clean Install". This option will essentially set up your device as if it was brand new, deleting any and all files in the process. This option should ONLY be used if a full backup of important files has been done to an external device, you are selling/giving the computer away, or there is a serious amount of malware present on the device (hacker programs)
7. Once you have decided which option is best for your use, finish the prompts in the window and let the device "do it's thing"
   1. Note that there will be multiple instances of the device restarting throughout this process, regardless of what option you chose for step 6
8. Make sure the device is plugged into its charger if it is a laptop, and simply wait for the process to be completed
   1. If you kept your personal files, you will need to log in with your password as usual, if you removed personal files, there will be no password, as the device will act like a factory new operating system.