Explaining Registry

When it comes to hacking XP, no other tool comes close to the Registry. It contains the underlying organization of the entire operating system, and its often-incomprehensible settings hold the key to countless hacks. In simpler days, one could hack Windows without bothering with the Registry; a solid knowledge of things like .ini files would suffice. But no longer. If you want to get hacking, the Registry holds the key—literally, since it's organized by way of keys.

If you haven't spent much time in the Registry, you can easily be cowed by it. At first glance, it's a maze of apparently incomprehensible settings. In fact, though, there's a method to the madness. The Registry is a hierarchical database of information that defines exactly how your system works, including virtually every part of XP and its applications. Editing the Registry database is often the best way to hack XP. In fact, there are many changes to the operating system that you can make in no other way.

Even if you've never used the Registry directly before, you've changed it without realizing it. Whenever you change a setting using the Control Panel, for example, behind the scenes a Registry change is made that puts that new setting into effect. The menus and dialog boxes you see in XP are often little more than a visual front-end to the Registry.

If you want to optimize XP and master every part of it, you'll have to use the Registry. XP contains so many different settings and customizations that it simply wasn't possible for Microsoft to build a graphical interface for every conceivable possibility. And there are many times when it's easier and you get more options when you edit the Registry rather than using the graphical XP interface. You can use Windows XP without ever editing the Registry—many users do—but advanced users understand its power tool status.

The way to edit the Registry is by using the Registry Editor , also called RegEdit. To run it, type regedit at the Run box or command line and press Enter.

Five Logical Registry Hives not wives

Following are the five hives and what each does:

HKEY_CLASSES_ROOT

This hive contains information about file types, filename extensions, and similar information. It instructs XP how to handle every different file type and controls basic user interface options, such as double-clicking and context menus. This hive also includes class definitions (hence the word "CLASSES" in its name) of unique objects, such as file types or OLE objects. Frequently, classes associated with file types contain the Shell subkey, which defines actions, such as opening and printing, that can be taken with that file type.

HKEY_CURRENT_USER

This hive contains configuration information about the system setup of the user that is currently logged into XP. It controls the current user's Desktop, as well as XP's specific appearance and behavior for the current user. This hive also manages network connections and connections to devices such as printers, personal preferences such as screen colors, as well as security rights. Also included in this hive are Security Identifiers (SIDs), which uniquely identify users of the PC and which have information about each user's rights, settings, and preferences.

HKEY_LOCAL_MACHINE

This hive contains information about the computer itself, as well as about the operating system. It includes specific details about all hardware, including keyboard, printer ports, storage—the entire hardware setup. In addition, it has information about security, installed software, system startup, drivers, services, and the machine's specific XP configuration.

HKEY_USERS

This hive contains information about every user profile on the system.

HKEY_CURRENT_CONFIG

This hive contains information about the current hardware configuration of the system, in the same way that HKEY_CURRENT_USER contains information about the current user of the system.