Windows 7: Possible to install windows XP x64 on an external hdd

I have an Acer laptop with windows 7 x64 installed and I want to know if it's possible to install windows xp x64 on an external hard drive. I modified the boot order in the bios to bdrom-external HD-main HD then started the instalation of xp to an active partition of the external HD (it has 2 partitions and only one is active) The instalation goes well untill it has to restart to continue the instalation, that's when "Ntoskrnl.exe is missing" message appears. Can boot normally to Windows 7 if I disconect the external HD but can't install xp on it.

Welcome!

Due to USB limitations, it is not possible to install to a USB device.

If you can take the drive out of the enclosure, you can try installing to the internal drive.

Maybe I'll test that out later today.

You cannot boot from an external USB drive. Every time you reboot, you will get that error.

JK...what's to test. If he removes the drive from the enclosure then connects it internally, of course it will install. It will now be an internal drive. If he then unplugs it and tries again to boot it from USB, he will get an error.

Ah... that's what I wanted to find out. Thank you tw33k.

My pleasure mate. (don't you love the team work here?)

Thanks for the feedback. So I'll have to manage partitions on the main hard drive to install the 2 OS's because windows 7 created an active 100MB partition making a total of 4 along with the c:, data and the Acer recovery partition. I cant create anymore partitions and my only choice is to delete the recovery one I think.

You can delete the 100MB system partition, if you want to free up a primary partition.

See my tutorial System Reserved Partition - Delete.

Good luck!

~JK

Is there any way to convert the C: and data partitions from two primary to one primary and one extended logical drive? That would also free up a primary.

You could always backup and use a third-party program such as Partition Wizard to do that.

Do note that a logical drive counts as a primary partition.

So he would have to create a extended DOS partitions with two logical partitions then. The first would be the C: Windows 7 boot drive and would be active, the second would be the D: data drive. That would only use up one primary partition.

That should work. That would leave the 100MB partition asis which I like as it provides access at boot time to the Repair Console and Memory tester.