You cannot start Windows XP in Safe Mode.

For more information about how to start your Windows XP-based computer in Safe Mode, click the following article number to view the article in the Microsoft Knowledge Base:

315222 A description of the Safe Mode Boot options in Windows XP

The problem is caused by a recently installed Microsoft software update, and you cannot solve the problem in any other way.

There is a registry problem that cannot be solved by using other tools such as System Restore.

You must apply default (file and registry) permissions to your Windows XP installation.

You must register Component Object Model (COM) components and Windows File Protection (WFP) files.

You must use the Windows Setup program to enumerate Plug and Play devices again, including the hardware abstraction layer (HAL).

Before you follow the steps later in this article, click the following article number to view the article in the Microsoft Knowledge Base if your computer came preinstalled with Windows XP: 312369 You may lose data or program settings after reinstalling, repairing, or upgrading Windows XP

If you perform an in-place upgrade of Windows XP, all existing restore points are removed and a new system checkpoint restore point is created after the in-place upgrade is completed. Do not perform an in-place upgrade if you may have to use System Restore to restore your computer to a previous state.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

301224 System Restore 'restore points' are missing or deleted

Backup copies of your registry files (in the %systemroot%\Repair folder) are also replaced after the in-place upgrade is completed. The registry files in the Repair folder are either from the first time that you started Windows XP or the last time that you used the Backup utility to back up your System State. Copy these registry backups to another location before you perform an in-place upgrade if you may have to use them after the in-place upgrade is completed.

Do not perform a repair or in-place upgrade to repair a component or program that is not currently installed. If you can, use the Add or Remove Programs tool in Control Panel, or reinstall the component or program instead of Windows.

If your computer requires a third-party mass storage device driver or HAL, make sure that you have a copy of the files on a floppy disk before you perform a repair or in-place upgrade.

Do not use a repair or in-place upgrade to try to resolve a problem with a user account, password, or local profile. To determine if the problem is related to a user account, password, or local profile, create another user account (if you can), and then log on to that account to see if the problem is resolved.

Do not use a repair or in-place upgrade to resolve a problem with third-party programs, files or registry entries.

Do not use a repair or in-place upgrade if you suspect disk problems.

Do not use a repair or in-place upgrade if you suspect a problem with a third-party device, and the latest device drivers are currently installed for the device.

1.

Start your computer.

2.

Insert the Windows XP CD in your computer's CD-ROM or DVD-ROM drive.

Note: If the service pack version of the operating system that you want to install is higher than the service pack version of the CD-ROM operating system that you own, integrate the service pack that you want into the Windows XP installation folder. For more information about how to integrate Windows XP Service Pack 2 files into the Windows XP installation folder, click the following article number to view the article in the Microsoft Knowledge Base:

900871 How to integrate Windows XP Service Pack 2 files into the Windows XP installation folder

3.

On the Welcome to Microsoft Windows XP page, click Install Windows XP.

4.

On the Welcome to Windows Setup page, click Upgrade (Recommended) in the Installation Type box (if it is not already selected), and then click Next.

5.

On the License Agreement page, click I accept this agreement, and then click Next.

6.

On the Your Product Key page, type the 25-character product key in the Product key boxes, and then click Next.

7.

On the Get Updated Setup Files page, select the option that you want, and then click Next.

8.

Follow the instructions that appear on the screen to reinstall Windows XP.

1.

Insert the Windows XP CD into your computer's CD-ROM or DVD-ROM drive, and then restart your computer.

2.

When the "Press any key to boot from CD" message appears on the screen, press a key to start your computer from the Windows XP CD.

Note: Your computer must be configured to start from the CD-ROM or DVD-ROM drive. For more information about how to configure your computer to start from the CD-ROM or DVD-ROM drive, see your computer's documentation or contact your computer manufacturer.

3.

You receive the following message on the Welcome to Setup screen that appears:

This portion of the Setup program prepares Microsoft Windows XP to run on your computer:

To setup 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 ENTER to set up Windows XP.

4.

On the Windows XP Licensing Agreement screen, press F8 to agree to the license agreement.

5.

Make sure that your current installation of Windows XP is selected in the box, and then press R to repair Windows XP.

6.

Follow the instructions that appear on the screen to reinstall Windows XP. After you repair Windows XP, you may have to reactivate your copy of Windows XP.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

310064 How to troubleshoot Windows XP Setup problems when you upgrade from Windows 98 or Windows Millennium Edition

Microsoft Windows XP Home Edition

Microsoft Windows XP Professional