Fix MBR or Operating System Not Found in Windows 7

  1. Set your BIOS to use the CD/DVD drive as the primary boot device.
  2. Boot with your Windows 7 installation disk or the Windows Repair disk.
  3. Press a key when the message indicating “Press any key to boot from CD or DVD …” appears.
  4. (Skip to step 6 if using a repair disk) Select a language, a time and currency, and a keyboard or input method, and then click Next.
  5. Click Repair your computer.
  6. In the System Recovery Options dialog box, choose your installation and click Next.
  7. In the System Recovery Options dialog box, click Startup Repair.
  8. If step 7 fails, click the Command Prompt and enter the command bootrec.exe /fixmbr(without the quotes)
  9. Reboot the computer with your fingers crossed.

Below are the images for the steps above.

Step 6


Step 7 or the beginning of Step 9


Step 9


If you have multiple partitions with different operating systems on them, this may not help you recover anything but Windows 7. Your best bet is to use a method to back up your boot settings before the inevitable problems occur. Another good safety measure is to completely back up your hard disk.

Even the smartest geeks mess up now and then. That’s how they learn. I’m hoping that your learning experiences don’t make you start swearing at the computer.

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Clif Sipe

Promoting Freeware and Free information since 2004. Owner of with over 2000 pages of freebies. Please subscribe to my Google Feed or follow me on Twitter @clifnotes.

  • Thanks man! Your steps were straight forward. The /fixmbr command did it for me, after encountering a grub rescue message (i had deleted a partition containing ubuntu).

  • Bijan

    My system only shows “operating system not found” and can not go further!
    Unfortunately, I didn’t build the Recovery DVDs before, so I borrowed my friend’s Recovery DVD to become able to start the system and go to recovery section.
    for your information, my laptop is “SONY VAIO VPC-F12FFX/B” and his model is “VPC-F111FX” that are very similar (but of course, their DVD can not use completely for another)

    The problem is that your step-by-step solutions seems to be OK (and its almost the same as Microsoft Solution Center and some other sites); but in this Algorithm, no one stated the point that our result is different than something that should appear there!


    Let’s return to my problem:
    In Step 6 , I should be able to see my missing operating system and of course, I should select it. But why nobody didn’t tell that if nothing shows, what should be our next step?

    Anyway, after doing some “try & error” ways, finally I become able to go to your 7 section titled “Select a recovery tool”
    As explained above, I couldn’t try “System Restore” (because Recovery DVD’s was not mine), and instead, I selected “Start up Repair” and followed its orders, but after restarting my computer, nothing solved :(

    I did it once again and then, I went into Command Prompt and tried “bootrec.exe” first with /fixmbr and then, with all of 3 other parameters (of course, I restarted my system after any changes)

    The only result is that my system error changed to:
    “BOOTMGR is missing”

    I know that there are special methods for solving this problem, but a very strange thing is that when I want to try the “System Restore” in “Select a recovery tool” section, windows will do some show-off and then says:
    “Startup Repair cannot repair this computer automatically”
    and wants me to “Send information to Microsoft”!

    for your information, problem details, as it says, are:
    Problem Event Name: StartupRepairOffline
    Problem Signature 01: 6.1.7600.16385
    Problem Signature 02: 6.1.7600.16385
    Problem Signature 03: Unknown
    Problem Signature 04: -1
    Problem Signature 05: ExternalMedia
    Problem Signature 06: 1
    Problem Signature 07: MissingBootManager
    OS Version: 6.1.7600.
    Locale ID: 1033

    My question is that, If we should try again the triple magic
    “bootrec /RebuildBcd” ,
    “bootrec /FixMbr” and
    “bootrec /FixBoot”,
    why the Microsoft “Startup Repair” program was not able to knew that?

    Oh! I tried of typing, I don’t know what happened to your mind :)

  • At step 6 it doesn’t find my windows 7 installation

  • angelobeltran

    What happens then if you have no os listed under STEP 6?