Article ID : S500029169 / Last Modified : 11/04/2018

Why does an error message appear and Windows® fails to start?

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Err Msg: Operating System Not Found.

This symptom occurs when the system files (files necessary for starting of Windows) cannot be found. The following are some causes of this symptom.

Note: User may wish to back up the data, when Windows restart to prevent any loss of data in future.

1. There is a floppy disk in the floppy disk drive.
Remove the floppy disk and restart Windows.

2. Sticking
If the VAIO computer is brought from a colder environment to a warmer one, a small amount of moisture in the air may condense on the head of the hard disk drive. This results in "sticking". If that happens, wait for a while. The condensed moisture will vaporize with the natural rise of temperature of the hard disk. Once the condensed mositure is vaporized, the system will start working normally.

3. The hard disk is not active or cannot be recognized.
If FDISK was executed just before this symptom started occuring, the hard disk drive may not be activated. Execute FDISK again and select 4 Display partition information to check the status of the hard disk drive. If A (which means "Active") does not appear under the status, the settings are not done properly. Select Set active partition to activate C:1. Restart the computer.

4. System files do not exist in the hard disk drive.
a. User can start Windows from the Recovery CD-ROM by inserting the Windows boot disk in the floppy disk drive. Execute the FDISK / MBR command to check if the system can recognize the hard disk drive.

b. If step A does not work and user has the Windows boot disk, start Windows with the disk. Execute the SYS command (A:\>SYS C:[Enter]) to transfer the system files to the hard disk drive.

c. Execute Recovery to install the system files to the hard disk drive.