virtualbox.org

Not sure if this is at all possible - I have upgraded a host machine from Windows Vista to W10 and need to install the XP Guest on Windows 10.
How do I do this?

Thanks,
Don.

Howto: Move a VM.

Thanks mpack - does it not matter if the windows host OS changes?

Not if you follow the instructions, and I'm also assuming you didn't override the folder structure of the VM (i.e. all files belonging to the VM are in the VMs folder).