erase files from a hard drive permanently

There’s two ways to permanently delete data. To permanently erase an entire hard drive including the operating system, you need to get a program that can be burned to a CD so you boot from that and erase the hard drive using the instructions on the CD. There are paid programs for this but for free, you can download Darik’s Boot and Nuke aka DBAN.

Just download it and follow the simple directions to burn a special CD. Then leave the disc in your CD drive and restart your computer. Immediately after it turns on press whatever key it says to load up a boot menu. Usually it’s F12 on modern computers. On an older computer it may be F8. On really, really old computers it can be ESC.

When the boot menu comes up, choose the CD drive and a small mini-operating system will load up and give you options on how to wipe your drive. With most it’s really straightforward. With Darik’s just press F3 to view the types of wiping or just type dod and hit enter. The reason this type of bootable CD, full hard drive wiping works far better than formatting is a little complicated. Basically formatting is like erasing a book’s table of contents but none of the actual text so it looks empty but really isn’t. It leaves the data sitting on the hard drive and says it’s available space to be overwritten. It’s still there until new data actually overwrites it. Bootable hard drive wipers change every single bit on the hard drive to 0 so the data is completely gone.

Of course, the previous method makes the computer totally unusable if you wipe the main system hard drive. This makes it hard to resell because it now has no operating system. Reinstalling Windows is a pain too so it’s only a really common method for businesses that rent computers. Rental companies have other, faster methods of making them useable again. If you want to just permanently delete a couple files and still leave your computer useable, keep reading.

Selective file deletion programs are traditionally called file shredders. A file shredder alternates between overwriting the files you select with all 0’s and all 1’s to make the file even harder to recover. A nice free shredder comes as a separate application with the installer for Spybot Search and Destroy. It’s called the Secure Shredder. You just drag and drop files you want shredded and hit go. It seems to get exponentially slower with large numbers of files though and doesn’t have any progress bar so you never know when it’s going to be done.

That’s a free way to get rid of a couple files quickly but if you regularly need stuff shredded, you’ll probably want to buy a better program for it. Search the web, there’s dozens of good ones out there. All programs work the same way though so either way, your files will be completely unrecoverable.