10 Things to Do Before You Wipe Your Computer

Before you sell or donate your used computer, how do you ensure the hard drive data is cleared? iStock/Thinkstock

You're upgrading to a new machine. Congratulations! What are you going to do with your old one?

You could sell it on eBay or Craigslist. But how do you make sure that the sensitive data on your PC — financial records, passwords to credit card Web sites, important e-mails, drunken pics from spring break — doesn't fall into the wrong hands?

Data thieves can use various programs to recover your sensitive files, even if you think you've deleted them. Just ask a British man who had to pay 100 pounds to a crook in Latvia to get back his old hard drive, after the crook mailed him a picture showing how he'd recovered his bank statements and a mortgage application. The man had been told earlier by a computer company that his faulty hard drive would be scrubbed when it was replaced [source: Arthur].

And this is not an isolated case. In 2009, British security researchers purchased 300 used computers from several countries and then perused the hard drives. They found that one-third of them still contained data from the former owners, including medical records from hospitals, proprietary business documents, and even test-launch information for ground-to-air missiles [source: Lamb].

But don't panic. Here are some tips on cleaning your computer so you can sell or donate it with no worries.