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I have Windows 7 pre-installed on my laptop, a Sony VAIO EB46FG. I successfully installed Fedora 16 in a dual boot configuration. I was able to use both OSes for few days. However, now I'm getting a GRUB error saying "unknown filesystem". The error started when I created a partition in the available free space. I did not modify the other partitions. I have made a live USB for Fedora and booted it, but a strange thing happened: the USB is not booting either.

I have very important data on the laptop. I just want to back into Windows.

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Mount the Hard drive in another machine and retrieve your data. Then format and reload the OS – Christopher Wilson May 2 '12 at 2:37
up vote 1 down vote accepted

The grub bootloader has somehow become damaged or confused. I believe when you added the new partition, it changed the order number of the partitions that grub is aware of. If you just want to boot back into Windows and don't care if you lose the ability to boot into Fedora (for now), you can easily fix that. (Here is a similar discussion on U&L).

The ultimate goal is to restore the Master Boot Record (MBR) to the hard drive, removing Grub, so you can boot to your Windows partition.

The easiest way to achieve this is to boot from your Windows 7 installation media. Use the Repair computer link and choose Command Line. At the command line, enter bootsect /nt60 SYS /mbr. You can reboot your system and it will now boot into Windows.

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Issue is solved.. now THANKS FOR YOUR HELP... I made another LIVE USB. and ubuntu on it. It boots and then i access the hard drive from local drive. then uninstall the grub from the boot partition and reinstall .. works fine THAKS GOD.. You guyz are really good. – alee-sindhu May 3 '12 at 0:44

To me, the strange thing is that USB booting does not work. Does fedora use grub when booting from USB? I would try another Live linux, eg. ubuntu or knoppix.

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Adding a partition has probably effectively renumbered the existing partitions.

I would suggest to delete the added partition, in order to reset the partitions order to what it was before.

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