OK, i'm officially no use now, as I have set my outlook to backup to the external e-drive, so all the default settings are gone. I do remember though that the file sits somewhere weird.
Someone has very kindly taken over our computer, and found that by adding the new software, the email configeration was knocked out! He did say its very unusual for this to happen, but thank goodness it is now working.
Thank you to everyone for your prompt replies. It servies to highlight the power of networking