INSTALL WINDOWS XP PROFESSIONAL FROM A MASTER IMAGEIN THIS EXERCISE, Y...

4-3). The Registry might contain several control sets, depending on how often you

change or have problems with system settings.

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You can view the current control sets using Registry Editor.

The CurrentControlSet subkey is a pointer to one of the ControlSet00x keys. The Clone

control set is a clone of the control set used to initialize the computer (either Default

or Last Known Good), and is created by the kernel initialization process each time you

start your computer. The Clone control set is not available after you log on.

To better understand control sets, you should know about the Registry subkey

HKEY_LOCAL_MACHINE\SYSTEM\Select. The entries contained in this subkey

include the following:

Current Identifies which control set is the CurrentControlSet. When you use Control

Panel options or the Registry Editor to change the Registry, you modify informa-

tion in the CurrentControlSet.

Default Identifies the control set to use the next time Windows XP Professional starts

unless you select the Last Known Good configuration. Default and Current typi-

cally contain the same control set number.

Failed Identifies the control set that was designated as failed the last time the com-

puter was started using the Last Known Good control set.

LastKnownGood Identifies a copy of the control set that was used the last time the

computer started Windows XP Professional successfully. After a successful logon,

the Clone control set is copied to the Last Known Good control set.

Each of these entries in HKEY_LOCAL_MACHINE\SYSTEM\Select takes a

REG_DWORD data type, and the value for each entry refers to a specific control set.

For example, if the value for the Current entry is set to 0x1, the CurrentControlSet

points to ControlSet001. Similarly, if the value for the Last Known Good entry is set to

0x2, the Last Known Good control set points to ControlSet002.

How to View and Edit the Registry Using the Registry Editor

Setup installs Registry Editor (REGEDIT.EXE) in the %systemroot%\System32 directory

during installation. However, because most users do not need to use Registry Editor, it

does not appear on the Start menu. To start Registry Editor, click Run on the Start

menu, type Regedit, and then click OK.

Although Registry Editor allows you to perform manual edits on the Registry, it is

intended for troubleshooting and problem resolution. You should make most configu-

ration changes through either Control Panel or Administrative Tools. However, some

configuration settings can be made only directly through the Registry.

Caution Using Registry Editor incorrectly can cause serious, system-wide problems that

could require reinstallation of Windows XP Professional. When using Registry Editor to view or

edit data, use a program such as Windows Backup to save a backup copy of the Registry file

before viewing. In Windows XP Professional, you can use Backup to back up the System State,

which includes the Registry, the COM class registration database, and the system boot files.