I had windows server 2008 installed on my machine and had several linux VMs running on it. I had problem running a piece of code which needed OpenGL 3.3 on my VMs so I decided to install Ubuntu directly on my machine using Wubi.

I ran the installer and after the first restart, Ubuntu installation screen comes up but at some point of time, it give me "No Root File System Defined" error which is impossible to get rid of. Also, every time I restart my machine, It goes strait to Ubuntu installer!

I wanna know how I can just revert back to windows? ( precisely, how can I just cancel the Ubuntu installation for good and have my windows back?)


If you have your Windows Installation media, I would suggest running startup repair off of that disc. That will overwrite your current bootloader with Windows' default which should allow you to boot Windows. Inside of Windows, Ubuntu should be listed as an installed program in Add/Remove Programs (which is what WUBI does). If you 'uninstall' Ubuntu, any changes made to your computer should be undone and you should be very close to where you started.


Here is how to boot back to Windows Server 2008 R2 if your Ubuntu installation goes wrong (or in general, how to do a start up repair on Windows Server 2008 R2):


You will need a Windows 7 x64 DVD.

  1. Boot from your Windows Server 2008 R2 x64 DVD.
  2. Repair
  3. Command Prompt

Note: I only had one drive and that drive was set for C: as the boot so the setup was fairly basic... if your setup is more complex you may want to consider this a bit more... but it should still work.

  1. rename c:\boot\BCD bcd.old : this will backup your bcd file just in case you want it.
  2. Delete c:\boot\bcd
  3. Restart your computer
  4. Remove your WS2008R2 DVD and install the W7x64 DVD.
  5. Boot from the DVD and do a repair.
  6. It will offer to repair automatically accept.
  7. Reboot and this is the "trick" boot the DVD again and do a repair. Keep doing this process until it does not find anything wrong.
  8. Your server should boot again.

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