Thanks for all the help.
As many people enquired, yes I am using a partitioned drive, and I've now installed the software, and worked out a lot about using Linux in the process!
Unfortunately, the modem still doesn't work, so I'm still using Windows to access the internet. The problem seems to be that my particular modem isn't supported.(It is a cheap and nasty insurance replacement after a lightening strike took out my computer - I accepted the naff modem because the computer was three times as powerful!)
Thanks again.
Dave.