“Error loading operating system” after installing Windows XP on separate partition from Windows 7

Question

I was trying to install Windows XP on a separate partition from my Windows 7 (RC) installation, but after the first reboot of the Windows XP setup, I get "Error loading operating system" and the system halts.

Here are the exact steps I followed:

1. Installed Windows 7 on a clean drive - Windows created a 100MB system partition, then I created a 350MB partition for the O/S, and I left 125GB unallocated.
2. Installed Windows XP in a new partition allocated from 125GB unallocated space.
3. After first reboot of Windows XP setup, I get "Error loading operating system".

I attempted to fix the problem using the "Startup Repair" tool on the Windows 7 installation DVD, and although it found a "master boot record corruption" and fixed it, I still get the same error after rebooting.

Answer 1

Windows 7 would have to be the last OS installed. The XP bootloader may be unable to handle Windows 7, but the other way around is likely fine. Try fixing your mbr (/fixmbr) from a Win 7 recovery console.

Answer 2

I can confirm that the XP bootloader does not handle Windows 7 well, and that even reinstalling XP over a HD that previously had windows 7 on it can be a hairy experience.

Standard practice for multibooting Windows is to install OS versions in order from oldest to newest, and so far as I am aware this may even be a MS recommendation, with other install orders being unsupported.

I would recommend to blow away both OSs and start from scratch again in the correct order (i.e. XP first).

Answer 3

Windows 7 doesn't play nice with other operating systems on the same box unless they're also Windows 7. So you'll probably have more luck installing Windows XP first, and then putting 7 on another partition (oldest first). I haven't tried this, so it comes with a disclaimer.

Answer 4

I dont think Windows 7 agrees with older OS's being installed after it. If its not too much work, I would recommend just blowing everything away, installing XP, then installing Windows 7 after it. I think thats your best bet.

Answer 5

It took me 3 hours but I managed to get around the "error loading operating system" problem with installing windows XP to dual boot with a pre-existing installation of windows 7. I have posted my solution on my blog if anyone is interested. Installing Windows XP to dual boot on a Windows 7 system

Hope this helps.

Answer 6

Install EasyBCD Free version (bottom of the page) in the OS that is bootable, run easy BCD and repair the Windows 7 bootloader, then add XP back into the Windows 7 bootmanager