When it's time to replace your computer, it's easy to recycle the old one. Many retailers accept old technology for free recycling, and charities like Goodwill have partnered with tech companies to keep computers out of landfills. But before you donate, be sure to do one thing: Erase the hard drive. There are software programs that literally erase the entire hard drive for you, or you can follow the manufacturer's instructions to do it yourself. You can also physically remove the hard drive and destroy it to keep your private information away from identity thieves.