"Operating System Not Found" error message appears when starting up and resolves

Operating System Not Found" or "Missing operating system" appears when starting a Windows XP-based computer (missing operating system) Error Messages This is an explanation in Microsoft's official support dictionary.

Overview When you try to start a Windows XP-based computer, you may receive an error message that the operating system cannot be found.

Symptoms When you start your Windows XP-based computer, you may receive one of the following error messages: Error message 1Operating system not found. Error message 2Missing Operating System when you start your computer and enter the recovery console to recover When you receive a feature, you may receive an error message that resembles the following error message: Setup did not find any hard drives installed on your computer.

Causes may occur if one or more of the following conditions exist Problem: • The basic input/output system (BIOS) cannot detect the hard disk. • The hard drive is damaged. • Sector 0 of the physical hard drive has an incorrect or corrupted Master Boot Record (MBR).

Note: Some third-party programs or disk damage can damage the MBR. • Marks incompatible partitions as active partitions. • The partition containing the MBR is no longer active.

Solution To resolve this issue, use one of the following methods, depending on your situation:

The best way to contact your hardware manufacturer may be with the manufacture of a computer or hard drive. Contact with the business. Manufacturers may have utilities that can be used to perform more detailed scans of damaged areas of the disk and to help verify proper BIOS settings. However, please note that damage to the hard disk can be very serious. Sometimes this means your only solution is to replace the hard drive.

If there are no fixes or workarounds, you can try to resolve this issue using the “Advanced Troubleshooting" section.

Advanced Troubleshooting This section is for advanced computer users. If you are confused about advanced troubleshooting, you can ask someone for help or contact support. For information about how to contact Microsoft Support, visit the following Microsoft Web site: http://support.microsoft.com/contactus/(http://support.microsoft.com/contactus/) Method 1: Verify BIOS setup verification The computer's BIOS settings ensure that the BIOS can list and identify the hard disk. For information on how to verify the BIOS settings, see your computer documentation or contact your hardware manufacturer.

Verify your computer's BIOS After you have detected your hard drive, restart your computer and test to see if the issue is resolved. If the issue is not resolved, or if your computer's BIOS cannot detect the hard drive, there may be a hardware problem. Contact the hardware manufacturer for information on how to resolve this issue. It may be necessary to replace the hard drive.

For information about how to contact the hardware manufacturer, click the article number below to view the article in the Microsoft Knowledge Base: 65416 (http://support.microsoft.com/kb/65416/) Hardware and software vendor contact information, AK

60781 (http://support.microsoft.com/kb/60781/) Hardware and software vendor contact information, LP

60782 ( Http://support.microsoft.com/kb/60782/) Hardware and software vendor contact information, QZ Method 2: Using the Recovery Console In the Windows XP Recovery Console, use the fixmbr command to repair the MBR of the boot partition.

Warning: This command may corrupt the partition table if there is a virus or hardware issue. If you use this command, you may create a partition that is inaccessible. We recommend that you run anti-virus software and back up your data before using this command. If the fixmbr command detects an invalid or non-standard partition table signature, the fixmbr command prompts you to allow overwriting of the MBR. The fixmbr command is only supported on x86-based computers.

For more information about the Recovery Console, click the article number below to view the article in the Microsoft Knowledge Base: 314058 (http://support.microsoft.com/kb/314058/) Description of the Windows XP Recovery Console 307654 (http://support.microsoft.com/kb/307654/) How to install and use the Recovery Console for Windows XP Method 3: Change the active partition if the partition marked as active does not contain Windows XP The startup file, or the operating system of the active partition is different from or incompatible with Windows XP, you must mark the correct system partition as active before you can restart your computer. To do this, follow the steps below.

Note: There can only be one active system partition at a time. 1. Start your computer and enter the recovery console. For more information, click the article number below to view the article in the Microsoft Knowledge Base: 307654 (http://support.microsoft.com/kb/307654/) How to install and use the Windows XP Recovery Console 2. Type Diskpart and press Enter. 3. At the "DISKPART" command prompt, type List Disk and press Enter.

Write down the number of the disk you want to use. 4. At the "DISKPART" command prompt, type Select disk <DiskNumber>, and then press ENTER.

Note: <DiskNumber> is the number of the disk to use. You should receive a message similar to the following: Disk <DiskNumber> is now the selected disk 5. At the “DISKPART” command prompt, type List partition, and then press ENTER.

Write down the number of the partition you want to mark as active. 6. At the "DISKPART" command prompt, type Select partition <PartitionNumber>, and then press ENTER.

Note: <PartitionNumber> is the number of the partition to be marked as active. You should receive a message similar to the following: Partition <PartitionNumber> is now the selected partition 7. At the "DISKPART" command prompt, type Active, and then press ENTER. 8. At the "DISKPART" command prompt, type Exit, and then press ENTER. 9. Restart your computer.