I have seen some clever looking software: http://www.microspot.co.uk/products/interiorsPro/index.htm
which I was thinking of getting as it would help me with what I want to do, turns out its only available for Mac OS.
Is there any possible way to install it on Windows?

Thanks for any advice

As they have examples on their site, you can use google sketch up or 3d studio, or autocad. But what I found the best tools for floor design of my house was http://v3.planningwiz.com/
And the best part, it's free! You can print or save your sketch... it's marvelous! ))))