Formatting your hard drive will delete everything on it, so make sure that all of your important files are backed up somewhere safe. Click here for instructions. The easiest way to format your hard drive is to reinstall your operating system, which will format the drive in the process. You will need your Windows 8 installation DVD in order to do this.  Note: This guide will walk through the steps for formatting and installing Windows 8, but you can use this method with any version of Windows or Linux. Most versions of both Windows and Linux have very similar installers that will guide you through the process. If you only have an ISO file for your operating system, click here for instructions on burning it to a DVD so that you can boot from it.  The key to open the BIOS menu is typically F2, F10, F11, or Del. Your computer will display the proper key before Windows loads. If your computer is booting too fast to enter the BIOS, click here for instructions on forcing the Advanced Startup menu to appear. This will allow you to change the order of devices that your computer tries to boot from. This will make your computer try to boot from the DVD first, allowing you to start the Windows 8 installation. Your computer will reboot. The setup program may take a few minutes to load. This will begin the installation process. This is a 25-character key that is unique to your copy of Windows. You will need this key in order to proceed with the installation. You can usually find the key on your installation disc's case, affixed to your computer, or in the confirmation email for your online purchase. This will allow you to format your drive before reinstalling Windows 8. In general, it is recommended that you never select an "Upgrade" installation. While this will save your data and installed programs, it will often lead to errors and software conflicts. This will not be present if you are installing Windows 8.1. If you are reinstalling Windows 8, select the drive that currently contains Windows 8. This will format the drive using the NTFS file system, which is the file system used by the Windows operating system. Next to proceed with the Windows 8 installation. For more details on installing Windows 8, click here.

Summary:
Backup any important data. Insert your Windows 8 DVD. Restart your computer. Open your computer's BIOS menu before Windows boots. Open the BOOT menu in your BIOS. Set your DVD drive as the primary drive. Save your changes and exit the BIOS. Press any key when prompted to start the Windows 8 installation. Click the "Install now" button. Enter your Windows 8 product key. Click "Custom" asked what kind of installation you want to do. Click "Drive options (advanced)". Select the partition that you want to format for Windows 8. Click "Format". Click .