If you cannot use a third-party tool, the XP install disc offers a limited wipe. Boot from the XP CD, enter the Recovery Console, and use the format C: /fs:NTFS /p:1 command. The /p:1 flag passes zeros over every sector once. This is less thorough than DBAN but acceptable for non-sensitive reuse.
If you are wiping a secondary drive (not the one Windows is installed on): how to wipe hard drive windows xp
: Go to Control Panel > User Accounts , create a new administrator account, then log out of your old one and into the new one. If you cannot use a third-party tool, the