Help File: Wiping data from an old PC or Mac
Q: How do I wipe my data from my old computer?
A: This evergreen task remains difficult because deleting files through the Recycle Bin or the Trash only clears a computer's record of their locations.
In Windows, install the free, open-source Eraser (eraser.heidi.ie) to scrub files completely. In Mac OS X 10.3 or newer, the Finder's "Secure Empty Trash . . ." does the same job (in OS X 10.1 or 10.2, use older releases of the free Permanent Eraser from the "Downloads" page at edenwaith.com).
But some critical data hides in obscure, even invisible locations. Digging up things such as saved e-mail, one folder at a time, can get beyond tedious. Instead, create a new user account just for erasing your data.
In Windows, open the Control Panel and click "User Accounts" (in XP) or "Add or Remove User Accounts" (Vista). Note your old account's name, then create a new account and pick "administrator" as its type.
Log out of the old account and into the new one. In the My Computer window, go to your computer's hard drive and open its "Documents and Settings" folder (XP) or "Users" (Vista). Right-click the folder named after your old account and select "Erase" to scrub it. Be aware that this will take many hours.
In Mac OS X, open System Preferences and select Accounts. Again, note your old account's name and create a new, administrator account.
Log out of your old account and into the new one. In the Finder, go to your Mac's hard drive and open its Users folder. Select your old account and use Secure Empty Trash or Permanent Eraser to wipe it.
Reload the computer's original software before selling or donating it. On a PC, you usually do that by starting it off a system-recovery partition, but check its manual for help. On a Mac, boot from the system CD or DVD and select its "Erase and Install" option .
The free, open-source Darik's Boot and Nuke (dban.org) can also wipe out everything on a PC if you'll only recycle it.
Next week: ways to donate or recycle old computers and electronics.