There are several ways to erase the contents of a hard drive. But the technique you use will depend on what you want to use the hard drive for afterwards. For instance, if you just plan on reinstalling Windows, it isn’t necessary to do a Department of Defense level shredding of your data
Erase your hard drive for reinstalling Windows
In newer versions of Windows, you can simply boot to the Windows CD and during the setup process, tell Windows to delete the current partition and install on the new partition. This will wipe out what you already had and replace it with a fresh, shiny Windows installation. Brand name computers--such as Dell, HP, Compaq and Sony—will ship with a recovery disk. You can use that recovery disk in place of a Windows CD to format and reinstall automatically.
Erase you hard drive and sell it on Ebay
If you plan on selling the computer or hard drive on Ebay or even at a yard sale, you must use a shredding utility that will thoroughly erase the data on the hard drive. Actually, these programs write 1s and 0s over every sector of the hard drive several times so the data that had been there is most certainly gone forever. You can then reinstall Windows, if you wish. The problem with the first method is that even though the drive has been formatted, there are tools available that can recover the data that had been erased. Using a program like Darik’s Boot and Nuke (or DBaN) will make that data unrecoverable.
Discarding a dead hard drive
If your computer has failed and the hard drive is no good, you must destroy the hard drive before tossing it in the trash. Sophisticated tools can be used to recover the data on hard drives that no longer work. If you plan on recycling the computer or putting it in the landfill (shame on you), you have to remove the drive and carefully destroy it by whatever means necessary. You can remove the platters by opening the hard drive shell. Whether you plan on drilling holes in it, smashing it with a hammer or driving over it with your car, be sure to wear protective goggles and gloves.
So there are different reasons for erasing your hard drive and different methods based on those reasons. You can find hard drive utilities on our Software Downloads section or contact us on our forums for more advice on how to handle data on your hard drive.