Install Windows 8 by turning on the PC and inserting a flash drive or DVD that contains the Windows 8 operating system. Turn off the PC, and turn it back on. Press the key needed to boot either the DVD or the flash drive, and then start the installation.
Before installing Windows 8, find the product key. The product key is located on the box in which the DVD was sold, or in a confirmation email if you purchased the operating system digitally. After entering the product key, Windows presents you with a license terms page. You must agree to the license terms to continue with the installation process.
Windows then prompts you with two options. You can install Windows 8 as an upgrade, retaining all of your old files, settings and applications, or a custom setting that installs Windows 8 without preserving old data
After you choose the installation process, Windows 8 asks you where to install the operating system. Select a hard drive for installation, and wait for the process to complete. Once Windows 8 finishes the installation process, you have the option to personalize the operating system. After this stage, the process is complete, and you can now log in.