To wipe a hard drive means to completely erase the drive of all information. Deleting everything does not wipe a hard drive and formatting does not [always] wipe a hard drive. You'll need to take an extra step to wipe the hard drive completely.
When you format a hard drive or delete a partition, you're usually only deleting the file system, making the data invisible but not gone. A file recovery program or special hardware can easily recover the information.
If you want to make sure that your private information is gone forever, you'll need to wipe the hard drive using special software.
Important: See Tip #2 at the bottom of the page for a huge exception in Windows 8, Windows 7, and Windows Vista.
Follow these steps to completely wipe a hard drive:
Backup anything you want to keep. When the hard drive wipe is complete, there will be no way to get anything on the drive back.
Important: Sometimes multiple drives exist on a single hard drive. You can view the drives (volumes) that sit on a hard drive from the Disk Management tool in Windows.
Download a free data destruction program. I recommend DBAN because it's easy to use and can wipe a hard drive from outside of Windows.
However, if another program in the list suites you better, by all means use it instead.
Note: There are actually several ways to completely erase a hard drive but using data destruction software is the easiest and still allows the hard drive to be used again.
Wipe the hard drive according to the program's instructions.
Note: Most data destruction program utilize several different methods to wipe a hard drive. If you're curious about the effectiveness or methods used to complete the hard drive wipe, see Data Sanitization Methods.
After properly wiping a hard drive, you can be confident that whatever information was on the drive is now gone for good.
Wiping a hard drive is operating system independent. That means that you can use this same general process to wipe a hard drive if you have Windows 8, Windows 7, Windows Vista, Windows XP, Linux, or any other PC operating system.
Beginning in Windows Vista, the format process changed and a single write zero pass is applied to each standard (non-quick) format. In other words, a very basic hard drive wipe is performed during a format.
If a single write zero pass is good enough for you, consider your drive wiped after a regular format in Windows 8, Windows 7, and Windows Vista. If you want something even more secure, go ahead and follow the hard drive wipe instructions above.
Keep in mind, too, that this is a wipe of just the partition you're formatting. If you have more than one partition on a physical hard drive, you'll need to format those additional drives as well if you want to consider the entire physical disk as "wiped".