Thank you for your replies, but I don't think Iexplained myself very well. I only have an educational version(ProE Student 2000i) for 'playing' with, and it is installed on my desktop PC at home. But now I work away sometimes in the week. So, if I installed my ProE Student on my laptop (if I get one), would I be able to open, use and modify the files I'd created on one computer on the other one? I'm not trying to get the files into a commercial licence (I don't have access to one).... I just want to be able to carry on with my 'hobby-modelling' in the evenings when I'm away from home.