I did what I thought was a clean install of xp pro --I think it has installed itself on both the C and D partitions --if so can this be easily fixed or will I have to re-install and re- activate with Microsoft again??

Best advice would be to start over.
I would remove all current partitions and recreate them as needed.
Also make sure you run a format as well.

If you haven't changed any other hardware, Windows will activate itself. You won't even see it happen. I would reformat and start over