Options for Systems That Will Not Boot Normally

Sometimes changes to system configuration settings or the installation of a new device driver or application may create a problem that prevents Windows XP Professional from starting normally. When this occurs, administrators can try the three following options:

• Safe Mode

• Last Known Good configuration

• Recovery Console

Safe Mode

Windows XP Professional provides several alternate startup modes that administrators can use to boot a computer in the event that an application, software driver, or configuration change prevents it from starting. These modes start Windows XP Professional using a reduced set of system files, drivers, and services. This reduces the complexity of the operating environment while providing the administrator with the ability to access the operating system in order to reverse any recent changes or diagnose problems.

Windows XP Professional provides three different Safe Mode options, as listed below.

• Safe Mode. Starts Windows XP Professional with a limited set of system files, services, and device drivers. Access is limited to the keyboard, mouse, disk, and the display (in basic VGA mode).

• Safe Mode with Networking. Starts Windows XP Professional with a limited set of system files, services, and device drivers. In addition, basic network services are started, allowing the administrator to access information and support tools located on the network.

• Safe Mode with Command Prompt. Starts Windows XP Professional with a limited set of system files, services, and device drivers. However, the Windows XP graphical user interface is not loaded. Instead, only the Windows XP command prompt is displayed.

In addition to the three Safe Mode options, Windows XP Professional provides a number of other special startup options, as listed below.

• Enable boot logging. Logs information about events that occur during the boot process into a file named Ntbtlog.txt, which is located by default in C:\Windows. Administrators can use the information located here to determine what services and drivers fail to load during system startup.

• Enable VGA mode. Starts the computer using the basic VGA driver, allowing administrators to recover from situations where display settings have been incorrectly configured.

• Last Known Good configuration. Boots Windows XP Professional using the startup configuration that was saved the last time a user successfully logged in to the computer. More information on using the Last Known Good configuration is available later in this chapter.

• Debugging Mode. Starts Windows XP Professional while simultaneously transmitting debug information to another computer using a serial connection.

By booting a computer using a Safe Mode option or one of the other modified boot settings, an administrator can bring the computer to a state where problems can be corrected. For example, accessing the Windows XP Display Setting dialog and adjusting color and resolution settings can correct an improperly configured display setting. Similarly, the administrator can fix many disk drive problems using the CHKDSK command.

The following procedure outlines the steps involved in altering the normal Windows XP Professional boot process.

1. Start the computer.

2. A message appears asking for the selection of the operating system. Press the F8 key.

3. Use the Up and Down Arrow keys to select a startup option that is appropriate for the situation and press Enter.

4. Correct the error that has been occurring and restart the computer normally to verify that the problem has been resolved.

Last Known Good Configuration

Many startup problems occur as a result of a configuration change made during the previous login session. The problem is not discovered until the computer is later restarted, at which time the error occurs. It is important that administrators educate users not to attempt to log in to Windows XP Professional at moments like these and instead to ask for assistance.

Each time the user successfully logs in to Windows XP, a collection of system configuration information is copied to the Last Known Good configuration. By default, Windows XP boots using its normal default configuration. However, in the event that a configuration change introduced during the last login session creates a problem, an attempt can be made to start the computer using the configuration settings stored in the Last Known Good configuration. The computer is then restored to its previous state before the configuration changes were made. However, if the user continues to log in after seeing errors during startup, the Last Known Good configuration is updated and may include the errors as part of its stored settings.

The Last Known Good configuration can also be used to try to start a computer that is unable to boot. For example, if the administrator installs a new hardware device whose device driver wreaks havoc on the computer and prevents startup using Safe Mode, it will not be possible to roll back the driver using Driver Rollback. In this case, the administrator could try restarting the computer using the Last Known Good Configuration, which would eliminate reference to the new software driver.

The following procedure outlines the steps involved in booting a computer using Windows XP Professional's Last Known Good configuration.

1. Start the computer.

2. A message appears asking for the selection of the operating system. Press the F8 key.

3. Use the Up and Down Arrow keys to select the Last Known Good configuration option and press Enter.

4. Select the operating system to be started and press Enter.

As soon as the computer is started, the computer's current configuration settings are recorded and a new Last Known Good configuration is created.

Recovery Console

If Safe Mode and the Last Good Known configuration are not able to assist in the resolution of a system problem, the administrator may be able to boot the computer using the Recovery Console to repair a Windows XP Professional installation. In order to use this utility, the password associated with the local Administrator account must be supplied. Unlike a computer booted using the Safe Mode with Command Prompt option, the Recovery Console supports only a limited set of Windows commands, as specified in Table B.2.

Table B.2: Windows XP Recovery Console Commands

Commands	Description
ATTRIB	Modifies file and folder attributes
BATCH	Runs commands stored in a text file
BOOTCFG	Modifies the boot.ini system file
CD	Changes the current working directory
CHKDSK	Analyzes and fixes problems with disk drives
CLS	Clears text from the display screen
COPY	Copies a file to the specified folder
DEL	Deletes the specified files
DIR	Displays all the files and subfolders located in a specified folder
DISABLE	Disables device software drivers and Windows XP services
DISKPART	Configures hard disk partitions
ENABLE	Starts device drivers and Windows XP services
EXIT	Terminates the Recovery Console and restarts the computer
EXPAND	Extracts the specified file from compressed .cab files located on the Windows XP Professional CD
FIXBOOT	Creates a new partition boot sector
FIXMBR	Repairs a disk's MBR (master boot record)
FORMAT	Formats a disk drive or floppy disk
HELP	Displays the list of the commands supported by the Recovery Console
LISTSVC	Displays a list of drivers and services
LOGON	Initiates a command line login session
MAP	Displays a list of currently mapped drives
MD	Creates a new folder
MORE	Displays a text file a screen at a time
NEW	USE Establishes a mapped network drive
REN	Renames the specified file
RD	Deletes or removes the specified folder
SET	Displays or modifies environmental variables
SYSTEMROOT	Changes the working directory to the %systemroot% folder of the Windows installation to which the administrator logged in
TYPE	Displays the contents of a text file without opening it

Using the Recovery Console, an administrator can start and stop system services, disable device drivers, execute commands to repair the master boot record, manage disk partitions, and even access network drives. The Recovery Console can be started in two ways, as listed below.

• From the Windows XP Professional CD

• By adding a Recovery Console entry to the list of Windows Startup options

Running the Recovery Console from the Windows XP CD

The Recovery Console can be loaded by booting the computer using the Windows XP Professional CD. This allows the Recovery Console to be run without preinstalling it on the computer. The following procedure outlines the steps involved in loading the Recovery Console using the Windows XP Professional CD.

1. Insert the Windows XP Professional CD in the computer's CD-ROM drive and start the computer.

2. The Welcome to Microsoft Windows XP screen appears.

3. Select Install Windows XP.

4. Select New Installation when prompted to select an installation method and click on Next.

5. Click on Next to accept the Windows XP Professional License Agreement.

6. Type the 25-character product key and click on Next.

7. When prompted to download updated setup files, select Yes, download the updated Set files and click on Next.

8. Windows Setup copies installation files from the Windows XP Professional CD and restarts the computer.

9. The Welcome to Setup screen appears, displaying the following options:

   • To set up Windows XP now, press Enter.

   • To repair a Windows XP installation using Recovery Console, press R.

   • To quit Setup without installing Windows XP, press F3.

     Press R.

10. When prompted, type the password associated with the Administrator account and press Enter.

11. Execute any of the commands listed in Table B.2.

12. When done working with the Recovery Console, type Exit and press Enter.

13. The computer restarts.

14. Press the F3 twice to exit the Windows XP Setup program and restart the computer normally.

Preinstalling the Recovery Console

If desired, the administrator may add the Recovery Console to the list of Windows XP Professional startup options, allowing it to be executed without the Windows XP Professional CD. The following procedure outlines the steps involved in adding the Recovery Console as a Windows XP Professional startup option.

1. Insert the Windows XP Professional CD in the computer's CD-ROM drive and start the computer.

2. Click on Start and then Run. The Run dialog appears.

3. Type X:\i386\winnt32 /cmdcons and press Enter (X: is the drive letter assigned to the computer's CD-ROM drive).

4. Click on Yes when prompted to install the Recovery Console.

5. A pop-up dialog will appear once the Recovery Console has been configured. Click on OK.

Once installed, the Recovery Console can be selected by pressing the F8 key when prompted to select an operating system during system startup and then using the Up or Down Arrow keys to select the Recovery Console option.

Removing the Recovery Console Startup Option

In the event that the Remote Console is no longer required as a Windows XP startup option, the administrator can delete it using the following procedure.

1. Click on Start and then My Computer.

2. Open the drive where the Windows XP system files reside.

3. From the root folder, delete the \Cmdcons subfolder.

4. From the root folder, delete the Cmldr file.

5. Modify the boot.ini file by deleting the following:

X:\cmdcons\bootsect.dat="Microsoft Windows Recovery Console" /cmdcons

Note 

If the Recovery Console file and folder are not visible within My Computer, select Tools and then Folder Options. Then select the View property sheet, clear the Hide protected operating system files option, select the Show hidden files and folders option, and click on OK.

Note 

For instructions on how to modify the boot.ini file, refer to "Configuring the Windows XP Boot Process" in Chapter 12, "Configuring and Administering System Files."