No operating system is found when a Windows Vista-based computer is started, even though the computer has been operating correctly for some time

You may experience the following problems on a Windows Vista-based computer that is using an NVIDIA nForce 430/410 (also known as MCP 51) Southbridge chipset:

• When you start the computer, no operating system is found. Additionally, you may receive an error message that resembles the following:
  No Operating System (OS) Found
  This problem may occur even though the computer has been operating correctly for some time. For example, the computer may have been operating for hours, for days, or for weeks. When you examine the NTFS file system boot sector, the NTFS boot record may have been moved by a multiple of 4 bytes.
• Random data corruption may affect any files on the computer.

This problem may be caused by multiple-queue "read and write" operations that occur at the same time. The data in a given sector may be randomly shifted by a multiple of 4 bytes. However, the sector itself is not changed. This problem may occur on the boot sector or may affect any file on the computer. For example, the problem may affect the following types of files:

• picture files
• image files
• movie files
• data files
• encrypted files

If you are using an NVIDIA nForce 430/410 Southbridge chipset, we recommend that you avoid this problem by installing a driver update for the device. To do this, visit the following Microsoft Web site: If your computer is affected by this problem, one of the following driver updates will be listed on the Windows Update page:

• NVIDIA Corporation driver update for NVIDIA MCP61 Serial ATA Controller
• NVIDIA Corporation driver update for NVIDIA nForce 430/410 Serial ATA Controller
• NVIDIA Corporation driver update for NVIDIA nForce 590/570/550 Serial ATA Controller
• NVIDIA Corporation driver update for NVIDIA nForce4 Serial ATA Controller

The driver update is listed as an optional update and has a publish date of 3/5/2007 or a later date.

Alternatively, contact NVIDIA to obtain a driver update that resolves this problem. For information about your hardware manufacturer, visit the following Web site: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.