How to Delete All Data on Your Computerby Chris Hoffman ; Updated September 28, 2017
Computers store your personal data on internal hard disks. When you delete a file from your hard disk, the computer removes the pointer that identifies the file, but it doesn’t immediately overwrite its data. People with file recovery tools could scan the hard disk for deleted files and access them. If you’re disposing of your computer or hard disk, deleting all data on the computer ensures no one can recover your sensitive information. You can download a free program that overwrites all data on your computer’s hard disk, making it unrecoverable.
Open the Darik’s Boot and Nuke download website at Dban.org/Download in your Web browser. Click the “DBAN for CD-R and DVD-R Media” link to download the DBAN ISO file. Double-click the downloaded ISO file, insert a writable CD or DVD and click “Burn.” Restart your computer, type “autonuke” at the DBAN prompt that appears and press “Enter.”
Navigate to the Ultimate Boot CD download Web page at UltimateBootCD.com/Download.html in your Web browser and click one of the “Download” icons on the Web page to download the Ultimate Boot CD ISO file to your computer. Double-click the downloaded ISO file, insert a writable disc and click “Burn.” Restart your computer, select “HDD” in the menu that appears with the arrow keys, press “Enter,” select “Disk Wiping,” press “Enter,” select “HDDErase” and press “Enter.” Type “Y” and press “Enter” at the confirmation prompts.
Go to the CBL Data Shredder download form page at CBLTech.ca/DownloadForm.php in your Web browser and fill out the form to receive a download link. Click the “CD-ROM ISO” link in the email you receive to download the ISO file in a zip file. Double-click the “CBL_Data_Shredder-DOS-CDR-IMAGE-en.zip” file on your computer, then double-click the ISO image file, insert a writable disc and click “Burn.” Restart your computer, select a hard drive with the arrow keys, press “Enter,” select one of the wipe options, press “Enter” and press “Enter” to confirm.
These programs delete every file on your computer, including your operating system and installed program. After running one of them, you can’t boot to Windows without reinstalling it.