Microsoft Knowledge Base Article 305478 contains the following summary and introduction:

SUMMARY

This article describes how to create and use a password reset disk for a computer that is not a member of a domain in Microsoft Windows XP. If you experience problems, troubleshooting steps are provided at the end of this article.

INTRODUCTION

This article describes how to create and use a password reset disk for a computer that is part of a workgroup, or that is not connected to a network. You can use a password reset disk to gain access to your Windows XP-based computer if you forget your password.

For additional information about how to create a password reset disk for a computer that is a member of a domain, click the following article number to view the article in the Microsoft Knowledge Base:

306214 How to create and use a password reset disk for a computer in a domain in Windows XP