When your system seems to power up okay, but the Windows XP operating system won't boot properly, you have to begin troubleshooting and if necessary get into the operating system, determine the problem, and then fix it. To help you get started, here are some things you can do when Windows XP won't boot.
Use a Windows startup disk
One of the first things you should reach for when troubleshooting a Windows XP boot problem is a Windows startup disk. This floppy disk can come in handy if the problem is being caused when either the startup record for the active partition or the files that the operating system uses to start Windows have become corrupted.
To create a Windows startup disk, insert a floppy disk into the drive of a similarly configured, working Windows XP system, launch My Computer, right-click the floppy disk icon, and select the Format command from the context menu. When you see the Format dialog box, leave all the default settings as they are and click the Start button. Once the format operation is complete, close the Format dialog box to return to My Computer, double-click the drive C icon to access the root directory, and copy the following three files to the floppy disk:
• Boot.ini
• NTLDR
• Ntdetect.com
After you create the Windows startup disk, insert it into the floppy drive on the affected system and reboot the computer. When you boot from the Windows startup disk, the computer will bypass the active partition and boot files on the hard disk and attempt to start Windows XP normally.
Use Last Known Good Configuration
You can also try to boot the operating system with the Last Known Good Configuration feature. This feature will allow you to undo any changes that caused problems in the CurrentControlSet registry key, which defines hardware and driver settings. The Last Known Good Configuration feature replaces the contents of the CurrentControlSet registry key with a backup copy that was last used to successfully start up the operating system.
To use the Last Known Good Configuration feature, first restart the computer and keep tapping the F8 key. This will display the Windows Advanced Options menu. Use the up and down arrow keys to make your selection. Select the Last Known Good Configuration item from the menu and press [Enter].
Remember, you only get one go with the Last Known Good Configuration feature. If it fails to work on the first attempt, the backup copy is also corrupt.
Use System Restore
Another tool that might be helpful when Windows XP won't boot is System Restore. System Restore runs in the background as a service and continually monitors system-critical components for changes. When it detects a pending change, System Restore immediately creates restore points, of these critical components before the change occurs. In addition, System Restore is configured by default to create restore points every 24 hours.
To use System Restore, first restart the computer continually pressing the F8 key. Now, select the Safe Mode from the menu using the up/down arrow keys and press [Enter].
Once Windows XP boots into Safe mode, click the Start button then access the All Programs < Accessories < System Tools menu, and select System Restore. Because you're running in Safe mode, the only option on the opening screen of the System Restore wizard is Restore My Computer To An Earlier Time, and it's selected by default, so just click Next. Then, follow along with the wizard to select a restore point and begin the restoration procedure.
Use The Recovery Console
When a Windows XP boot problem is severe, you'll need to use a more drastic approach. The Windows XP CD is bootable and will provide you with access to a tool called Recovery Console.
To boot from the Windows XP CD, insert it into the CD-ROM drive on the problem system and reboot the computer. Once the system begins booting from the CD, simply follow the prompts that will allow the loading of the basic files needed to run Setup. When you see the Welcome To Setup screen press R to start the Recovery Console.
Fix a corrupt Boot.ini
As the Windows XP operating system begins to load, the Ntldr program refers to the Boot.ini file to determine where the operating system files reside and which options to enable as the operating system continues to load. So if there's a problem rooted in the Boot.ini file, it can render Windows XP incapable of booting correctly.
If you suspect that Windows XP won't boot because Boot.ini has been corrupted, you can use the special Recovery Console version of the Bootcfg tool to fix it. Of course, you must first boot the system with the Windows XP CD and access the Recovery Console as described earlier.
To use the Bootcfg tool, from the Recovery Console command prompt, type
Bootcfg /parameter
Where /parameter is one of the required parameters listed in the table below.
Parameter
/Add Scans the disk for all Windows installations and allows you to add any new ones to the Boot.ini file.
/Scan Scans the disk for all Windows installations.
/List Lists each entry in the Boot.ini file.
/Default Sets the default operating system as the main boot entry.
/Rebuild Completely re-creates the Boot.ini file. The user must confirm each step.
/Redirect Allows the boot operation to be redirected to a specific port when using the Headless Administration feature. The Redirect parameter takes two parameters of its own: [Port Baudrate ] [UseBiosSettings].
/Disableredirect Disables the redirection.
Fix a corrupt partition boot sector
The partition boot sector is a small section of the hard disk partition that contains information about the operating system's file system (NTFS or FAT32), as well as a very small machine language program that is crucial in assisting the operating system as it loads.
If you suspect that Windows XP won't boot because the partition boot sector has been corrupted, you can use a special Recovery Console tool called Fixboot to fix it. Start by booting the system with the Windows XP CD and accessing the Recovery Console as described earlier.
To use the Fixboot tool, from the Recovery Console command prompt, type
Fixboot [drive]:
Where [drive] is the letter of the drive to which you want to write a new partition boot sector.
Fix a corrupt master boot record
The master boot record (MBR) occupies the first sector on the hard disk and is responsible for initiating the Windows boot procedure. The master boot record contains the partition table for the disk as well as a small program called the master boot code, which is responsible for locating the active, or bootable, partition, in the partition table. Once this occurs, the partition boot sector takes over and begins loading Windows. If the master boot record is corrupt, the partition boot sector can't do its job and Windows won't boot.
If you suspect Windows XP won't boot because the master boot record has been corrupted, you can use the Recovery Console tool Fixmbr to fix it. First, boot the system with the Windows XP CD and access the Recovery Console as described earlier.
To use the Fixmbr tool, from the Recovery Console command prompt, type
Fixmbr [device_name]
Where [device_name] is the device pathname of the drive to which you want to write a new master boot record. For example, the device pathname format for a standard bootable drive C configuration would look like this:
..Device..HardDisk0
Disable automatic restart
When Windows XP encounters a fatal error, the default setting for handling such an error is to automatically reboot the system. If the error occurs while Windows XP is booting, the operating system will become stuck in a reboot cycle—rebooting over and over instead of starting up normally. In that case, you'll need to disable the option for automatically restarting on system failure.
Restore from a backup
If you can't seem to repair a Windows XP system that won't boot and you have a recent backup, you can restore the system from the backup media. The method you use to restore the system will depend on what backup utility you used, so you'll need to follow the utility's instructions on how to perform a restore operation.
Perform an in-place upgrade
If you can't repair a Windows XP system that won't boot and you don't have a recent backup, you can perform an in-place upgrade. Doing so reinstalls the operating system into the same folder, just as if you were upgrading from one version of Windows to another. An in-place upgrade will usually solve most, if not all, Windows boot problems.
Performing a Windows XP in-place upgrade is pretty straightforward. To begin, insert the Windows XP CD into the drive, restart your system, and boot from the CD. Once the initial preparation is complete, you'll see the Windows XP Setup screen (shown earlier in Figure A). Press [Enter] to launch the Windows XP Setup procedure. In a moment, you'll see the License Agreement page and will need to press [F8] to acknowledge that you agree. Setup will then search the hard disk looking for a previous installation of Windows XP. When it finds the previous installation, you'll see a second Windows XP Setup screen on the next page.
This screen will prompt you to press R to repair the selected installation or to press [Esc] to install a fresh copy of Windows XP. In this case, selecting a repair operation is the same as performing an in-place upgrade, so you'll need to press R. When you do so, Setup will examine the disk drives in the system. It will then begin performing the in-place upgrade.
