If you run out of options, my recommendation would be to back up your personal data and installed programs, and then perform one of the recovery options available to you through Windows 8. Swipe in from the right side, or point with your mouse to the bottom right corner of your screen. Click Settings, Change PC Settings, Update and Recovery, Recovery, and then choose the option that best matches your needs.
Understand that you can lose personal data and installed programs that are not backed up.