Fixing Windows Master Boot Record (in dual boot machine)

1 minute read

I had been having an issue with my dual boot computer (Ubuntu 10.10 and Windows 7) where every time I wanted to boot up into Windows I got a dark screen with a blinking cursor.  I knew that the master boot record had been corrupted somehow and had to fix this.  I resisted the urge of having to re-install Windows as I knew what was wrong, but just didn’t know how to fix it.  After a short search, google once more came to the rescue.  With the Windows 7 DVD, you can boot up into repair mode, choose a command prompt and type in the following command:

bootrec /fixMBR
bootrec /fixBoot
bootrec /rebuildBCD
bootrec /scanOS

The last command gave me a result that ‘0’ installations of Windows were found, this was not correct however.  Afterwards, I rebooted the machine and I was able to get into windows!  The only problem now was that my Grub menu was not showing up so that I could choose either Ubuntu or Windows.  To fix this, I followed the steps  on the link below (I had to use the installation CD for Ubuntu 10.10 to fix the issue).

Boot Repair

I choose sdb as my drive, as this was my secondary drive where both Linux and Windows are installed.  The only other thing I had to do afterwards was to remove the extra Windows 7 loader menu that showed up, so I typed in the following code:

sudo chmod +w /boot/grub/grub.cfg

I then removed the extra Windows 7 entry by using my favorite editor vim

sudo vim /boot/grub/grub.cfg

I saved my changes and then rebooted the machine and all of the OS entries I wanted were listed!

Note: After modifying the grub.cfg file, there are instructions to run

sudo grub-update

However, if I do this … I still get the duplicate Windows 7 entry in the Grub boot menu.

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