I want to install Windows XP on a desktop, the original media for which is long lost. I haven't been able, so far, to use the key on the sticker on the case, probably because none of my XP images are exactly the right OS version to accept the key, and I've heard that XP is finicky about that.
I have a known good image and key that I used to install a XP home on a virtual machine. When I use them to install XP on my target, however, I still get an "invalid key" error message. This happens during the OS install, long before it would have a chance to phone home (I've retired the VM in question, but that shouldn't matter anyway).
What could be going wrong?