How To Clean Install Windows 10

In this article, we will see how to re-install Windows 10 if you have it set up already, or how to install the OS from scratch. This can be done on both UEFI and legacy BIOS computers.

It is assumed that your computer fits the minimal system requirements for Windows 10. They look as follows:

• CPU: 1 GHz or faster
• RAM: 1 GB for 32-bit or 2 GB for 64-bit
• Free disk space: 16 GB for 32-bit or 20 GB for 64-bit
• GPU: DirectX 9 or later with WDDM 1.0 driver
• Display: at least 800x600 screen resolution
• Internet access to activate the OS

Also, see the following articles: Windows 10 system requirements and Microsoft has revised system requirements for Windows 10

Pre-requirements

First of all, you need to create a bootable media if you don't have one. It can either be a bootable USB stick or an ISO image written on a DVD. Refer to the following articles:

• How to install Windows 10 from a bootable USB stick
• How to create a bootable UEFI USB drive with Windows 10 Setup
• Create Windows 10 Bootable USB Stick With PowerShell

If you don't have an ISO image, you can download it from the official Microsoft web site as described in the article Download Official Windows 10 ISO Images Directly Without Media Tool. If you prefer the Media Creation Tool method, it is described in detail here. It is an official tool, which also can be used to download the ISO image.

Finally, you need to learn which key you should press to enter the UEFI environment or BIOS boot menu on your computer. The key might be different on each PC, so you might need to carefully observe at startup which key is specified or try pressing them to see which of them activates the UEFI or BIOS environment when the PC is just starting up, before Windows has begun loading. Refer to your device's manual.

After entering the UEFI or BIOS boot menu, set the options as required to boot first from DVD or USB before the computer attempts to boot from your internal disk drive. Once this is configured, when the Windows installation DVD is inserted or bootable USB is connected, the PC will boot from it and not from your internal storage.

When Windows Setup begins from USB or DVD, it will show you a progress bar for some time and then enter a graphical environment. If you have a high DPI display, the UI elements might look very tiny because DPI scaling is not enabled at this stage.

Clean Install Windows 10

1. Start your device from a bootable media with Windows 10
2. Wait for the following dialog and select your language, time and currency, and keyboard options.
3. Click on the Install now button to proceed.
4. Enter your product key if you have one. If you previously had Windows 10 installed with a Microsoft account, the license will already be tied to your account. Once you sign in with that same account after installing the OS, it will become activated automatically, so you can omit the product key in this case. See this article for details: How to link your Windows 10 license to a Microsoft Account.
5. If you have Windows 10 installation media with multiple editions, select the edition for which you have a license, when prompted.
6. Check the I accept the license terms box to accept the licence.
7. On the next page, click on the option Custom: Install Windows only (advanced). This will allow you to perform a clean install. Do not perform an upgrade install even if you have the option as a clean install has several benefits.
8. Select a partition to install Windows 10 on. If you don't have any partition, you can create one or just select unallocated space in the list. Windows 10 will automatically format it and create extra partitions for the boot manager, BitLocker etc as required and/or UEFI partitions. In the last case, it will create either 450 MB (UEFI-GPT) partition or 500 MB (Legacy BIOS-MBR) System Reserved partition.
9. The following window indicates that the installation process is going on. Wait till the computer restarts.
10. In recent builds, you'll see the Cortana assistant which will guide you for further steps.
11. Select your region and keyboard. You can add extra keyboard layouts if required.
12. If your device comes with a wireless adapter, you can connect it to a wireless network.
13. On the screen How would you like to set up, choose a suitable option. Set up for an organization is required when you need to join a domain. Set up for personal use is suitable for home PCs.
14. On the next page, fill in your Microsoft Account details or click on the Offline account link to set up Windows 10 without a Microsoft account. Also, you can create a new Microsoft Account if your computer is connected to the Internet.
15. I'm installing the OS without a Microsoft account. On the next page, it is required to confirm your decision by clicking No.
16. Specify your user name and password.
17. If you've set a password, you will be prompted to add security questions to your local account.
18. On the next page, you will be asked to enable or disable Cortana to assist you during your user session. Choose what you actually want.
19. You will be prompted to customize your privacy options. Disable the required options.

You are done! Windows 10 will prepare your user account.

After a minute or so, you will see your Desktop. Now it is time to install your favorite desktop and Store apps, and change the operating system's options according to your preferences using the Settings app and Control Panel.

That's it.