Create Windows 10 Installation Media

Windows 10 Installation Media Tutorial

Download Windows 10 ISO files

Official Microsoft Link - Windows 10 ISO

Select Windows 10, then choose your language, then press one of the download options.

In most cases, download the 64-bit edition. Legacy PCs may require the 32-bit edition.
(If you are unsure about which edition your PC needs)

Create a bootable USB

Download the Windows USB/DVD Download Tool

Run the downloaded file and install.

Open the Windows 7 USB/DVD Download Tool from your start menu and select the Windows 10 ISO file.

Erase the USB, let it finish creating the USB, and you're done!

Create a bootable DVD

Follow the steps above, and select the DVD option instead of USB. It may take a little while due to the way burning a DVD works. This requires a DVD-R with 4.7 GB of space.

Boot to USB

1. Restart your computer and wait for that first screen to pop up. Often, it'll say something like "Press F12 to Choose Boot Device" somewhere on the screen. Press that key now.
2. Give it a moment to continue booting, and you should see a menu pop up with a list of choices on it. Highlight your CD or USB drive and press Enter.

If you are unsure, Google your computer followed by "boot to USB". On most computers, F12 is the boot menu key.

Install Windows

Follow the above tutorial and you'll be good to go. If you want to completely wipe the computer, delete every partition that appears. Make sure to select the correct disk, or the drive you want to install Windows on. It will reboot automatically.