Before trashing your old computer, protect your information, erase your data securely

Once you've set up that brand new shiny PC or laptop, it's time to ditch the old clunker taking up coveted space under your desk. Before you sell or donate your old PC, however, ensure that the information you stored on it doesn't fall into the wrong hands.

Back Up Your Data. First, make sure you get everything you need off your old system because the rest of this process is irreversible. Don't count on your memory of what files are important -- take a complete disk image of your computer to capture everything from data to bookmarks and application settings.

Windows users can try DriveImage XML ( Free to use, it creates a cloned image of your hard drive that can be restored directly from drive to drive without having to reboot. It also allows you to use your computer in tandem while it backs up your data silently in the background.

Mac users should consider SuperDuper ( Basic features are free, including easy instructions and complete cloning of your hard drive. Advanced features such as scheduled automatic backups and software updates are available for around $30.

Since you're taking the time to backup your data, it may be worth considering transferring your files to a cloud application such as Carbonite or Mozy. Carbonite includes software to automate transfer to your new PC and data storage is unlimited (, HomePlus Plan is $99/yr)

Deauthorize All DRM'ed Software. When you make digital purchases online, most of them come with digital rights management (DRM) that limits their use to only a few devices. ITunes, for example, limits files to five devices and they add up quickly. For iTunes specifically, sign into your account and navigate to the iTunes store. Click on Manage Devices and remove your old PC from the list. Don't forget to check other accounts that you have DRM'ed materials with, such as Adobe Creative Suites and Amazon Kindle.

Securely Reformat the Hard Drive. Simply reformatting your hard drive doesn't remove the data on it, just hides it from view and removes it from your system's index. A dedicated party can restore data from a formatted drive using recovery software. To securely delete your data, use a program that actually writes over the area of the disk where the file was stored (sometimes with multiple passes to be super safe).

Mac makes it simple in OS X. Use the Disk Utility found via the Tools menu. Choose Erase and Security Options, electing the more "secure" version. Windows users can use Darik's Boot and Nuke (, free) to reformat.

Re-Install the Operating System (OS). After you've reformatted your hard drive, your computer is essentially a blank slate. As a courtesy to your buyer, reinstall the OS. Hopefully, you hung on to all those system discs that came with your computer when you purchased it.

Windows will automatically boot from the disc once you power back on, but Mac users will need to hold down the Option key to start the process. A word of caution: if you don't have your install discs, don't be tempted to install something you don't have a license for. How far you go into the install process is up to you, but the easiest method is to just power off when the computer prompts you to create a user account and leave that set up for the new owner.

Finally, if you're planning to sell it give it a thorough cleaning with a Mr. Clean Magic Eraser and some compressed air. The nicer it looks, the better your chance to get top dollar.

Andrea Eldridge is CEO of Nerds on Call, a company based in Redding, Calif., that offers on-site computer and home theater set-up and repair. Contact her at

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