Probably, there is no need to explain how unpleasant the situation is when the user turns on the computer or laptop to boot and instead of the usual start, the system writes Operating System not found for no reason at all on the screen. For many users, this causes a real shock. How so? Yesterday, everything worked ... What could happen, and how to fix this situation, we will now see.
What does the Operating System not found error mean?
If you look at the message itself, it is easy to translate it as "the operating system was not found." But the trouble is, the user is absolutely sure that she is. But the computer system does not share such confidence with the user, because it simply does not find the components responsible for loading the system.
In general, such situations are most often manifested, for example, when a user removed a hard drive, replaced it with a new one. Maybe the hard drive just failed, but you never know what.
Possible causes
If such an incident suddenly happened, and the system constantly displays an Operating System not found message (Windows 7, 8, etc.), first of all, do not panic. To get started, just check, maybe a USB flash drive is inserted in the computer or laptop, and in the BIOS settings, the USB device is the priority for loading.
If the hard drive was removed or changed to a new one (this applies to stationary computers), it may very well be that when it was reconnected, the corresponding loops were incorrectly or loose. Let's see what can be done in such a situation.
The simplest BIOS settings
The easiest way to change the BIOS settings may be to reset all the settings to the factory defaults (Default). In any version of the BIOS there is such a setting.
In extreme cases, you can simply change the boot priority in the Boot Device Priority or Boot Sequence section, and install the hard drive as the first (main) boot device (boot device).
It happens, however, that the hard drive is detected in the BIOS, but loading is still not performed, and the system again and again displays the warning Operating System not found. What to do in such a situation? First, see if there is an exclamation mark in front of the hard drive model . It signals that the device in the system, although present, is simply disconnected or not involved.
As a rule, in most BIOS versions on the right there is a special field for device help (Specific Item Help), which indicates a keyboard shortcut that allows you to enable or disable any component. The most likely combination is Shift + 1. But here it all depends on the manufacturer (combinations may be different).
Switching Winchester Operating Modes in UEFI BIOS
On the other hand, if an Operating System not found warning appears on a laptop where it is quite problematic to remove the hard drive, you should pay attention to the settings of the hard drive operating modes separately. As an example, consider the settings of the latest UEFI system, although they can be used without problems in other versions.
In general, the SATA configuration has two main modes: AHCI and IDE. During the initial installation of the "OS", as well as in the default settings, AHCI mode is enabled. When you switch to the IDE, no matter how you try, installing Windows on the hard drive will fail.
The same applies to the moments when users, at the end of the installation process, either out of ignorance or accidentally turn on the IDE mode. As already clear, the system and displays the line Operating System not found. By the way, even if at the moment you put another fully functional “screw”, it will not work either without changing the SATA settings to the initial ones.
Therefore, you should immediately advise users to change such settings only in the most extreme case, when it is really necessary.
Windows bootloader recovery
There are also cases when the message “Operating System not found” appears when the Windows boot loader is damaged, which is associated only with errors on the hard disk, for example, due to an incorrect shutdown. In this case, as is already clear, the whole system can "fly off".
In this situation, you can try to restore the bootloader, and at the same time check the system drive or partition for errors. For this, it is always advisable to have the original installation disk or system disk for recovery at hand.
Here you will need to set the optical drive in the BIOS as the first priority device to boot, and then use the recovery console. Note that in this option there is no question of restoring Windows from a checkpoint. This still will not help, and the warning Operating System not found will appear again.
Here you need to use boot recovery mode or the command line, which is preferable. In it, you need to enter two main commands in succession: bootrec.exe / FixMbr and bootrec.exe / FixBoot, after each pressing Enter. If this sequence does not help, you can also add the bootrec.exe / RebuildBcd command.
Before performing such actions, it is strongly recommended that you check the disk for errors with their automatic correction (chkdsk / f / r or chkdsk / f / x / r commands). You can also use the chkntfs / xc checker: provided that the NTFS file system is in the system partition (drive "C").
If all else fails
However, if all of the above methods to correct the situation do not help, then you should definitely diagnose the hard drive. But if it is not a problem to remove it for stationary computers , then you will have to contact the nearest service center or workshop with a laptop and not try to remove it yourself.
As it is already clear, if the Winchester “sprinkled”, there is nothing to be done, you will have to change it to a new “hardware”, and then install the “OSes” again. You can, of course, try out the action of the HDD Regenerator utility on it , but it is quite difficult to guarantee absolute success in recovering a hard disk .