This article describes how to write zeros to a hard drive to erase all data on Windows 7 and later. Instructions include how to format the drive in a special way using the format command.

Since you can write zeros to a hard drive using the format command, both from within Windows 7 and Windows Vista, and from outside the operating system, we've created two ways to perform these instructions. This process can take anywhere from a few minutes to a few hours.

Create a system repair disc in Windows 7. To do this, you’ll need access to a Windows 7 computer. However, it doesn’t have to be your Windows 7 computer. If you don’t have a Windows 7 PC, find a friend who does and create a recovery disc from their computer.

If you don't have one or can't find a way to create one, you won't be able to write zeros to disk this way.