You should remove all of your personal or sensitive data before donating, selling, or recycling your old computer. After you have encrypted all of your data, you can look up your particular model online to see exactly where to locate your hard drive for removal. You will want to unplug everything first, touch something metal to discharge any static electricity, then find your hard drive and disconnect it. There may be some small screws holding the drive in place that you will need to unscrew carefully.