Friday, January 6, 2012

How to Wipe a Computer

I find myself leaving another job in favor of a better job.  Has happened quite a bit recently.  I wonder what that says about the economy?

Anyway, I've got another laptop I need to wipe clean before I can turn it back into my previous employer.  I figure, while I'm doing it, I might as well write down the various techniques.  You may want to do this anytime you're turning in an old computer or recycling it or giving it away.  Who wants to leave all that personal information on a computer!?

There are basically two options, the preference will be up to you.

Option 1 is to wipe the entire hard drive including the OS and all the files on it.  This will make the computer completely unusable until someone else loads an OS.  The nice thing about this method is that (with the exception of overwriting) you can be pretty sure that none of your data is going to persist.  All you have to do is get an OS boot disk.  If you have a windows installation disk hanging around, this will work.  If you don't, you could get a pirate copy (since you won't really use it for the OS) (disclaimer: it's still technically illegal).  If you're not comfortable with that, you can always download a copy of Ubuntu and burn it to disk.  Ubuntu is an operating system like Windows or Mac, but it's totally free.
Either way, put the disk in the drive and reboot the computer.  At some point before the windows logo comes up, you should get a prompt to boot to the CD.  Do what it says to boot to the CD.  Then go through the process of installing the OS.  Most operating systems will come to a point asking you where you want to install the OS.  This screen will usually show you what partitions currently exist on your hard drive.  You should see your Windows partition and maybe some unused space.  Use the options on the screen to delete the Windows partition and select it for the installation destination.  At this point, you're pretty much done.  The partition has been deleted, so it would be pretty hard to get your data from the hard drive at this point.  If you want to be really sure, go ahead and install the new OS.  This will overwrite your data with new data making it very close to impossible to get your old data back, even for magicians like me.  If you want to really screw stuff up, power the PC off while it's copying files onto the hard drive.  Just pull the plug.  It won't hurt the hardware, but the software will be completely corrupted.  Whoever wants to use it after you will have to do some work to get it working again, which will further obscure your old data.

Option 2 is to uninstall all your programs and delete your username and profile.  This one doesn't guarantee your data will be as hidden.  Basically go into the control panel and uninstall everything you remember installing.  You don't have to uninstall everything, since some things are required for the computer to function properly.  Obviously, you need to move your documents and other stuff from this computer to another computer you'll be keeping.  If that means copying to an external hard drive, that would work as well.
After you've uninstalled everything, go create yourself a new account.  This is pretty easy.  Just go into the control panel under users and create a new account.  Make it an administrator if you can.  Once you're done  with that, reboot your computer.  When the logon screen comes up, logon as the new user you created.  Then go into the control panel and delete your old user account.
To be doubly sure everything is deleted, go to the system properties dialog box.  In Windows Vista/7, you can find this by opening the start menu and typing 'environment variables'.  This should open a dialog box showing you a couple of options.  In the middle, there should be a section called 'User Profiles'.  Click the 'Settings' button there and you should be presented with a list of profiles on the computer.  Go ahead and select your old username (if it's still there) and click the delete button.  You can also delete any of the other profiles (except the Default Profile).  Shutdown your computer and you're done.  It's as clean as it will be without resorting to option 1.