Question about Outlook Express

Automatic address for hotmail.co.uk doesn't work with IE8. When replying to an email, the sender's address doesn't automatically appear.  Further, when starting a new message and typing in the addressee, nothing happens but a rotating green circle of dots appears.  This has only happened in the last month or so.  Have the security settings in IE8 changed?  How can I get back to what it was before?

There is no such problem when using Firefox.

Any helpful suggestions gratefully received.