How to Clean a Hard Drive Before Donating a Computer

By Contributing Writer

It is important to thoroughly clean out a hard drive before donating it, selling it or throwing it away. Computers are one of the largest sources of identity theft, and many people don't realize just how much personal information may be stored on their computer. Deleting files is not enough. The entire disk should be wiped clean and overwritten several times, before it can be considered safe.

Things You'll Need

  • Eraser (free open source program)


Step 1

Back up any data that you wish to keep onto another hard drive or another type of media.

Step 2

Physically remove the hard drive from your computer and reinstall it as a slave drive. Eraser, a free software program, can only overwrite files that are not in use. Thus, if an operating system is running on the drive in question then this data will not be possible to overwrite.

Step 3

Delete all flies on the disk. Open the newly configured slave drive via Windows and delete everything from the drive, including the operating system. Eraser works by overwriting unused space. Thus, a file must first be deleted in order to be overwritten.

Step 4

Download Eraser from the link provided, and install the program.

Step 5

Read the help file carefully. It contains detailed information on how the program works and how people go about recovering deleted files. Eraser has several options for how data is overwritten. It is important to understand these options in order to make a decision about managing your own security.

Overwriting the Hard Drive

Step 1

Run Eraser.

Step 2

Select "Edit" from the toolbar and then choose "Preferences" followed by "Erasing."

Step 3

Click on the "Unused Data" tab. This is the section where you choose your level of data security. Eraser works by overwriting deleted files. The more data is overwritten, the harder it is to recover. However, the more you choose to overwrite the data, the longer it will take to do so. You have the option of overwriting your file once with pseudo-random data, or you can overwrite it multiple times (there are several options). The choice is yours, but remember that since you are planning to overwrite an entire disk worth of information, it could take many hours or even a few days depending upon how large the disk is and how many times you decide to overwrite it.

Step 4

Make your choice and click "OK."

Step 5

Select "File" from the tool bar, and then "New Task." A new window will pop up.

Step 6

Check the box for "Unused Space" and choose the drive you wish to overwrite from the drop-down menu.

Step 7

Click "OK." The task will now appear on the task list.

Step 8

Click on the task you just created, and then press Ctrl+R (or select "Run" from the task menu on the tool bar) to start the erasing process. A progress meter will appear, showing you how much time is left to complete the process. There is a button to stop the process if necessary.

Tips & Warnings

  • No data deletion program can completely eliminate all remnants of a digital data file. It can only make it very difficult to recover. Remember that if someone is willing to put enough time and resources into it, any deleted file can probably be recovered. If you have critical data on your hard drive that your life depends on, and if you have reason to believe that someone else may have sufficient motivation and determination to reconstruct this data (even if it takes months or years), then do not rely upon Eraser or any other technology to delete it. Either physically destroy the hard drive beyond recognition, or keep it forever in a safe place.

References & Resources