My dad made 1,000 programs run and blew up the entire server and the hard drive was fried except for the plastic. (And I mean 1,000 programs of 5GB each in the program.)
The easiest way to destroy someone's hard drive would be to use a program that would wipe it clean. If you are looking for a manual option, you could remove the hard drive from the computer and destroy it with a hammer or use industrial magnets to wipe it clean.
Destroy it so it can never be run or looked at in any way
The best way would be to create a ghost image of the existing hard drive, that has all your files and copy it, into an external USB hard drive or a secondary internal hard drive. Some ghost software packages only cost a few bucks, but basic versions can be downloaded for free.
The most conventional way is to get a giant magnet, and slide it across your hard drive atleast 7 times. WARNING: Only do this if you truly want to destroy/erase it.
You can always install a fan in front of your hard drive to help it cool down, or put it in eco-mode.
To completely erase the information on your hard drive, you can try a third-party tool like iReaShare Data Wipe, which can completely erase your files, folders, hard drives, and external devices on a PC.
the best way is with an external hard drive
On the computer or a portable hard drive would be better
Using the Ultimate Boot CD. It is full of programs designed to completely wipe out data from your hard drive, the 1 program I use from it is called Darek's Boot 'n Nuke, when you use it, it's like you just walked out of the store with a new hard drive, NOTHING can be recovered.
If you have alot of data, you can buy and esternal drive, or buy a second hard drive, and put it inside the machine and use it as a back up storage drive. You can buy a decent size hard drive online shipped for 60 dollars or less.
Best way to do this is to simply reformat your computer/hard drive.
Defragment of your hard drive on a monthly basis is one way of maintaining the hard drive.