Outlook Express will allow you to define a 'Sent To' address - look under Tools, Message Rules, Mail and select New Message Rule.

What you will actually do is to set up a rule to filter out mail sent specifically to your correct address, which can go to a folder called, for example, 'Inbox 2' - from then on, all mail remaining in the original inbox will be spam, and you can 'Ctrl A' to mark them all, hit delete and they'll all go into 'Deleted Items'.

Okay, maybe it's a little inconvenient having two inboxes...!