Thanks for your comment. Yes, I think I have re-done everything. But after my latest attempt I have now got the message (below) from MS Outlook (which I don't normally use). As I normally just use Outlook Express, is this where my problem lies? How do I set the 'default mail client' to Outlook Express? Or do I have to use Outlook for the Emails to be sent? Although last month I'm pretty sure that I didn't have to use Outlook.

The error message said -
'Either there is no default mail client or the current mail client cannot fulfill the messaging request. Please run MS Office Outlook and set it as the default mail client.'

If I have to do this can you give me a steer as to how I do it please?