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Like many other Windows XP system components, the Registry is very much like the Windows NT/2000 Registry. However, there are also many differences, some of which are obvious (such as removal of the registry size limitation), while others are hardly noticeable. Mostly, the changes in Windows XP registry are due to the kernel enhancements introduced with this new release of the operating system. Throughout the book, I'll emphasize these differences and draw your attention to them. Windows XP Registry also contains a large number of new records. This isn't surprising, since each new registry entry corresponds to a new feature introduced with the new release. The registry is a centralized storage area for all the information on the hardware and software system components. Because of this, all new features introduced with Windows XP have to be reflected in the registry.

Can this book be considered a reference describing all registry keys, or a handbook of practical solutions for everyday work? Unfortunately, no, it cannot. I dream about a book like that myself! I also know what a bulky book that would be (if it's possible to write at all). My aim isn't quite so ambitious. In this book, I'll describe the important components of Windows NT/2000 and Windows XP registries, and emphasize the similarities and differences that exist between them. I'll also discuss various techniques of backing up and recovering the registry, and provide essential technical information on other aspects of working with the registry as well. I hope that this book will be useful for system administrators and advanced users who want to improve their knowledge of the Windows NT/2000 registry and get acquainted with the Windows XP registry. However, Windows XP is also positioned as an upgrade for Windows 98, Windows 98 SE, and Windows Millennium Edition (ME). Users who migrate to Windows XP from Windows 9x/ME must not be deceived by apparent similarities between Windows XP registry and the registries they are accustomed to. On the contrary, Windows XP registry is quite different!

Quite often, one may hear users say "I hate Windows registry because it is rather cryptic, contains tons of redundant information, and makes the system vulnerable, since Windows can't run without it". If you hate the Windows registry too, I am not trying to convince you to love it. After all, most people tend to hate a thing that they can't properly understand. I can also agree that this opinion is partially valid, because the registry actually is cryptic, difficult to understand, and really is required for the system to run. However, from this point of view, a human being is also very far from perfect, since the human body doesn't live without a brain (and even if someone supports this life artificially, how miserable it would be!). What I am really after is helping you understand the registry. Therefore, I didn't try to describe all known registry tips and tricks. Rather, I tried to explain how these tricks work and why they work at all. I think that when you get a sound understanding of the registry architecture, structure, and data types, you'll soon be able to discover such tricks yourselves.

Obviously, my own experiences of working as a technical support specialist have influenced both my methods of work in general and this book in particular. When I begin working with a new operating system, I'm mainly interested in providing a trouble-free environment—various aspects of backing up and recovering the more important system components (the registry, in our case), including non-traditional and rarely used ones. Various aspects of registry backup and recovery, together with methods of eliminating system failures, take priority in this book. I'm sure that before migrating to the new operating system and experimenting with it, the user will need to study these topics very carefully. Testing backup, restore, and troubleshooting procedures will also be helpful.

The book contains the following chapters:

• Chapter 1 contains an overview of Windows NT/2000/XP registries. It provides a brief description of registry structure, valid data types, and methods of storing Windows NT/2000/XP registry data. At the same time, it considers some Windows XP kernel enhancements that resulted in registry changes—for example, the removal of registry size limitation.

• Chapter 2 is dedicated to various methods of backing up and restoring the registry. Even the most experienced Windows NT/2000 user should read this chapter carefully, since these procedures have changed significantly in Windows XP.

• Chapter 3 discusses the user interface of the registry editor (Regedit.exe). Most experienced Windows NT/2000 users should remember that Windows NT 4.0 and Windows 2000 actually included two registry-editing utilities—Regedt32.exe, the more powerful utility with extended capabilities but an old-fashioned interface, and Regedit.exe—the newer utility with an enhanced UI, which lacked, however, some powerful features of Regedt32. In Windows XP, the situation has changed, and there is now only one registry-editing tool—Regedit.exe, which combines the functionality of the two registry editors. Beginners can use this chapter as a brief reference on this tool (which, by the way, Microsoft is positioning as one of the reliability enhancements).

• Chapter 4 looks at the simplest methods of configuring Windows XP. This chapter describes both the method of configuring the system using administrative utilities and the method that requires registry editing. Some of the tips provided here also apply to Windows NT and Windows 2000, while others are Windows XP-specific.

• Chapter 5 discusses the problem of storing hardware information in the registry. It also provides basic information on Plug and Play architecture implementation in Windows 2000/XP, including two new kernel-mode subsystems—Plug and Play Manager and Power Manager. Also covered are the OnNow initiative and the ACPI specification. Special attention is given to Windows XP-specific enhancements.

• Chapter 6 contains a detailed description of the boot process for both Windows NT/2000 and Windows XP. It describes the registry's role in the boot process and provides a brief overview of the methods of eliminating boot failures. Special attention is focused on Windows XP built-in reliability enhancements, including safe mode, Driver Rollback, Recovery Console, and code signing options such as Windows File Protection, System File Checker, and File Signature Verification.

• Chapter 7 can be used as a brief reference to the registry keys.

• Chapter 8 discusses network settings in the registry for both Windows 2000 and Windows XP.

• Chapter 9 has a special place in this book, because it discusses one of the most important topics, namely, various aspects of protecting and securing the registry.

• Chapter 10 discusses the problems of managing user working environments, including user profiles and group policies.

• Chapter 11 contains recommendations and tips on eliminating the most common problems (including boot failures) by means of editing the registry. It is of special interest for system administrators and technical support personnel.

• Chapter 12 is dedicated to advanced customization and troubleshooting topics.

• Chapter 13 provides a brief overview of the handy third-party registry utilities.

• Chapter 14 provides an overview of automating registry management using windows Script Host (WSH). Of course, it can't be considered a reference on Windows automation and scripting languages (this topic deserves a special book). However, we will consider the registry-manipulation methods provided by WSH, then create a simple example illustrating their usage, and then produce a small but really useful script.

• Appendix 1—Internet resources. If I intended to create a reference on the Internet resources dedicated to Windows 2000/XP, it would be a large book indeed! Of course, not all of these resources are equally useful. Because of this, I included only the most informative and reliable ones in the appendix.

• Appendix 2—Bibliography. This appendix provides a list of sources where the reader can find supplementary information concerning the topics discussed in this book.

• Appendix 3—Glossary.

To conclude this brief introduction, I would like to thank all the members of the A-LIST Publishing team for offering me the opportunity to work on this book.