Whether you are preparing to reuse a hard disk for another operating system, clear off your junk shelves by passing along outdated drives to a friend or relative, donate an old PC to a charity or school, discard a too-small USB drive or flash memory card, or repurpose an SSD, you don’t want to leave any information on the storage device. With stories abounding of identity theft aided by information lifted from discarded storage devices, you want devices you no longer plan to use to have no usable information when they head out the door.

When you erase/delete a file from your computer, it’s not really gone until the areas of the disk it used are overwritten by new information. If you use the normal Windows delete function, the “deleted” file is sent to the Recycle Bin until the space it uses is required by other files. If you use Shift-Delete to bypass the Recycle Bin, the space occupied by the file is marked as available for other files. However, the file could be recovered days or even weeks later with third-party data recovery software. As long as the operating system does not reuse the space occupied by a file with another file, the “deleted” file can be recovered.

In this article, we'll show you how to erase your drives the right way, leaving no trace behind.