This has been solved - I forgot to mark up the thread. Sorry.
The truth is, I tried to keep things simple by re-installing all my old software on my new machine. I did this on the basis of "If it works, don't mend it".
It was a dreadful mistake because the old stuff, consisting of various patches etc, could not really be re-installed in the form I was hoping for. What's more, the attempt thoroughly upset the operating system. I had to re-install it three times before I got things right.
In the end I bought all new software (I kept the XP Pro, but nothing else). New VS 2008, New Ipswitch FTP, New Office ... New everything.
Then it worked fine.