Is it possible to dual boot Windows 8.0 and 8.1 on the same machine using the same key, or will the licensing system detect two instances of Windows 8 on the same serial?
If that was originally a W8 system, then the BIOS has the W8 product key. Although you can upgrade that to 8.1, I would think that a W8.1 installation would not recognize that key.
The same if you reset the PC to factory settings, you end up with W8 which you will have to upgrade to W8.1 again.
I tried building a Hyper-V machine using the Win8.1 ISO so I could test things without breaking my live machine.
When I tried to activate, the original key was denied "This key is already in use on another machine"
[DEL]I don't think it is possible, although dual boot might make a difference since a VM is essentially a different machine.[/DEL]
It might be possible in a dual boot because the machine is the same machine. You should be able to use the 8.0 key to activate, that's the only key I have and I was able to download 8.1 (pre-Media Creation tool) and update to 8.1 using it.
A VM is essentially a different machine and that violates the license of only installed on one machine (even though it was a VM on the same physical machine)