Boyd, you could try another install with all your security and anti-virus programs disabled.
I used to have all kinds of weird problems (not just with CC stuff) when I had Norton.

Will try with security disabled; not using any theme. So far this is just a couple of lines of basic text, a photograph which I used on my previous website and a bar from the shapes menu from within VSD. In the meantime I've abandoned trying to do this on my windows 8 machines and have started the site on one of my older PCs running Windows 7 (with no issues whatsoever).

I've had absolutely no problems on Win7. Your switch is a good thing.