You could get away with an unregistered install of Win 7 or 10 to finish off your drawings. Fire up a virtual machine - VirtualBox is a free VM host. Thanks you all for the suggestions - looks like I need to find another PC. Install it on another device as it seems to recognise either IP or MAC addresses when you re-register.
I was too keen to download and play with Loopcad and unfortunately my 30 day trial has expired before I could finalise our ground floor plan.
