After spending the entire night googling this issue and finding that it's very common, I eventually unearthed a forum in which someone had found two ways of fixing it. One way, the simplest, was to ring a UK number and activate using an automated phone method. So I spend ages jabbing numbers into the phone keypad and writing down the numbers the female android gave me to complete activation.
So it's up and running. Having other minor problems. Good job I bought a massive Dummies book about Windows 7!
Thanks for all the help.