Accidentally marked a partition as “Active”, rendering computer un-bootable

Posted: March 27, 2012 in Uncategorized

Hey it happens to the best of us – you right-click and click something that just “felt” like the right one because you were moving too quickly…

First, don’t re-boot if you can help it. The solution is much easier that way.  If not, you’ll have to read down further for the solution.

If you haven’t re-booted yet

  • Click start, run, type “cmd”, press enter
  • Type “DISKPART”
  • Type “LIST DISK”
  • Look for the drive that you know is the one with the partition you marked active, you’re going to have to rely on the size of the disk
  • Type “SELECT DISK n” where n is the number of the disk
  • Type “LIST PARTITION”
  • Look for the partition you marked active. Again, you’re going to have to rely on size. If there’s only one it’s easy.
  • Type “SELECT PARTITION n” where n is the number of the partition
  • Type “INACTIVE”
  • You’re in the clear now, you can close the two command windows and re-boot safely

If you HAVE re-booted…

Well you need access to another computer and internet connection.  Follow my instructions for creating a Windows XP boot CD and use the same “DISKPART” instructions above to perform the same procedure.  You need to follow the instructions on that page for making a CD, not a USB, because the CD will give you all the tools you need, including DISKPART.  Diskpart will be one of the options in the menu when you boot off that CD.

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