As far as re-installing Windows is concerned, Windows 8 provides two options to its users– Reset PC & Refresh PC. Reset Your PC deletes all your data, apps, settings, passwords etc. and re-install a new copy of Windows. Refresh Your PC also re-install Windows but it save your data and most of the apps and settings.
Reset Your PC is the appropriate choice if you are planning to sell your computer. In such a case, you would definitely want to wipe off all your personal data, so that it could not be recoverable by any recovery software. You should use this option specially when your computer contain some sensitive information. When you use this option, your system will be booted in the Windows Recovery Environment mode that will format your hard drive and install a fresh copy of Windows.
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When you use Refresh Your PC option, the system will be booted in the Windows Recovery Environment mode. Your data, apps and settings, will be copied to a location using some imaging and migration technology a fresh copy of Windows will be installed and eventually, your data, apps and settings will be restored from the aforementioned location. When you restart your PC, all your data, apps, and settings are remained as they were before Windows was re-installed. Although this option will not be able to preserve various file type associations, display & firewall settings and desktop apps. In order to access Refresh Your PC option, open control panel, click “General” on the left sidebar and you will see a button to Refresh Your PC in the main window.