Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

So im getting the error "Error loading operating system" when the computer tries to boot to a fresh install of WinXP Pro.

To get to this point, I:

  1. Shrunk the only partition with Gparted to 33GB
  2. Copied the partition to the end of the 200GB drive
  3. Enlarged the first one to fill the space
  4. Formatted the first partition to NTFS
  5. Set the first partition to boot, tagged the latter to hidden, removed boot flag

This was done all under Hiren's BootCD. Now this is where it goes down the drain.

I installed XP Pro SP1a from its CD, and chose to quick format the partition. Now after the OS was installed, I can't start XP without using the default menu action from Hiren's BootCD. All I am greeted with is the "error loading operating system" message.

I tried to use the XP recovery to fixboot, fixmbr and bootcfg /rebuild (dont remember if the command was like this, anyway the 3 suggested commands). This did nothing.

What am I missing here?

share|improve this question
Slipstream SP2 or SP3 into your install cd, try again with a clean install. – Moab Sep 3 '12 at 21:12
Well, still couldn't fix it. But I think its issue with the bootflag set on the second partition and not on the first. And @Moab I can't reinstall the computer anymore, the worker took it into use, and I no longer have time to install it (Unless I stay overtime after work). – Jakesan Sep 4 '12 at 19:20
So, to repeat it, you changed the partition numbering and windows is now confused about which part is needs to boot from ? – Hennes Sep 24 '13 at 1:59

"Error loading operating system" occurs because boot sector is outside of BIOS addressable area of your boot device or boot sector does not contain 55 AA signature. Maybe active partition in MBR is just wrong?

Try fixing this error with EBCD Mount & Boot Center. It can verify entire boot chain from MBR to BOOTMGR and BCD. Also when you moved your partition, all references to it from BCD became invalid because such references consist of MBR signature and sector offset of partition, EBCD Mount & Boot Center can fix that too.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.