How do I reset someone's password?

With the native NET command:

    NET USER loginname newpassword /DOMAIN

With (native) Windows Server 2003 commands:

    DSQUERY USER -samid loginname | DSMOD USER -pwd newpassword

Note:

To prevent the new password from being displayed on screen replace it with an asterisk (*); you will then be prompted (twice) to type the new password "blindly".