Destroying a hard drive can me managed in different ways. Security is in degrees. The simplest and the least effective is setting you hard drive to factory setting. This DOES NOT destroy your personal information. Every piece of data that was ever on your computer is still there.
There are methods of wiping, degaussing and deleting. None of those methods will be as effective is shredding hard drives.
Secure on-site hard drive shredding is available for no charge for businesses in the Greater Tampa Bay Area and now, all of Florida, by Urban E Recycling.