This is part of the Reinstall and Reformat XP FAQ.
Here’s how to wipe a hard drive that uses NTFS as a file allocation system. (If you don’t know what that is see this article on What’s under your Windows XP hood?)
You can do this one of two ways by using the Windows XP startup disks or if your computer supports a bootable CD-ROM — most computers built since 2001 have this feature — use the Recovery Console tool on the Windows XP CD-ROM. More on that shortly.
First, remember that reformatting a hard disk deletes all of the data that is on it, so make sure that you back up your data before you reformat the disk. That data is unrecoverable afterwards. It’s gone forever.
Two ways to back up your data that we recommend are an online solution called Carbonite or purchasing back up software. A software title we recommend is East–Tec Backup 2007. For other software solutions, visit the TechnologyTips Software Library.
To use the Windows XP Recovery Console to reformat a drive, follow these steps:
Start the computer by using the Windows XP CD-ROM (in the CD-ROM drive) or the start-up disks (in the floppy drive).
You may need to go into your BIOS to change the boot sequence to make your CD-ROM drive the primary boot device. Take a look at this article on How to get into your computer’s BIOS to change the boot device order.
Once the computer has booted from the CD you’ll see a "Welcome to Windows Setup" screen appear and after all the drivers have loaded (shown along the bottom), press F10 or wait and choose to use the recovery console (choose item #2).
In the "Recovery Console" (learn more at the Microsoft web page on the Windows XP Recovery Console), specify the appropriate Windows installation. It will be listed. It’s probably #1. Then log on by using your Windows XP Administrator password. You are probably the administrator and the password if you have never assigned is probably blank, so just hit the Enter key. If you run Windows XP Pro and want to turn off the password prompt then take a look at this Microsoft article.
and hit the ENTER key.
Note the drive that you want to reformat. The drive letters may be different in the Recovery Console from what they are in Windows XP, but if you want to reformat the C: drive then its likely the largest. In some cases, it may not be the largest drive, so make sure you choose the correct drive when using the format command.
format C: /fs:ntfs
Or if you don’t want to format C, use the drive letter of the hard drive that you want to format. Hit your ENTER key.
Then press ENTER to continue. When the formatting process is finished, type
and then press the ENTER key to restart the computer.