How to clear all files from the computer

From ArticleWorld

There are some cases when you will want to delete all the files stored on a hard drive, ending up with a completely empty disk. This operation is called "formatting". Here is how to do it.

Steps

You will need a Windows XP floppy boot disk. Instructions for creating one can be found here: http://www.computerhope.com/boot.htm#71 .

1. Reboot your machine, booting from the floppy boot disk you created earlier. Note that you may have to change your computer's BIOS settings in order to instruct your computer to try booting from the floppy disk before attempting to boot from the hard disk. If your computer boots normally, without trying to read anything from the floppy, consult your motherboard's documentation.
2. When a command prompt (C:\>) appears, type 'FORMAT C:' (without the quotes) and press enter.
3. You will be asked to confirm this operation, as this will delete all the files from the C: partition. After you have confirmed, the operation will begin. Repeat the procedure for any other partitions you may have.

Notes

Formatting the hard drive will virtually remove the information stored on it. Since actually removing everything would take a long time, the format procedure doesn't really "erase" everything, but clears the signs that make information accessible as files. Information is overwritten in time, but it can still be restored at time. Some utilities claim to completely remove it, but even those are not 100% successful in all cases. If you are formatting a disk in order to destroy information completely, the most efficient way to do it is much more physical. After formatting the drive, take it out of the machine. Run a very powerful magnet on its sides, drill a few holes and then burn it or melt it. Of course this will destroy the hard drive, but it will ensure data is completely destroyed as well.