The registry is one of the most important part of the Windows Operating System. Any problem with the registry can have far reaching consequences. A corrupted registry can prevent Windows from even starting up.

In this article, we will show you how you can fix a corrupted Windows registry from an Ubuntu partition.

So, if there is some problem with your Windows registry and you cannot start Windows, here is what you can do:

• Boot into Ubuntu.
• Once in Ubuntu, open the terminal.
• Install NTFS-3G, with the command

sudo apt-get install ntfs-3g

• Install NTFSProgs

sudo apt-get install ntfsprogs

• Mount the NTFS partition:

sudo mkdir /media/windows

sudo ntfs-3g -o force,rw /dev/<device name> /media/windows

• Now we are all set to start fiddling with the registry. But before you do that, it would be advisable to back it up with the command:

sudo cp -r /media/windows/WINDOWS/system32/config/ /home/<user>/Desktop/

• Now copy the following files from the file /media/windows/System Volume Information/_restore{xxx}/RPxxx/snapeshot/ directory:
  

  _REGISTRY_USER_.DEFAULT
  _REGISTRY_MACHINE_SECURITY
  _REGISTRY_MACHINE_SOFTWARE
  _REGISTRY_MACHINE_SYSTEM
  _REGISTRY_MACHINE_SAM

  to the /media/windows/WINDOWS/system32/config/ dir and name them as follows:

  _REGISTRY_USER_.DEFAULT => default
  _REGISTRY_MACHINE_SECURITY => security
  _REGISTRY_MACHINE_SOFTWARE => software
  _REGISTRY_MACHINE_SYSTEM => system
  _REGISTRY_MACHINE_SAM => sam

• Schedule a consistency check with the command:

sudo ntfsfix /dev/<device name>/

• Reboot into Windows. You will get a screen telling you that you should run a filesystem consistency check. Let the check run and then the second reboot should bring you back into a bootable Windows.

[via Ubuntu Forum]