Outlook Express Pro 2003

I recently discovered some strange problem that I always thought would came from an email virus. Now I discovered it isn't. The following happened:

I received a mail from my father (so I can check what he did). He has send me 2x the same mail. I receive these 2 mails every time outlook makes a connection with the server. My father receives on return every time a "read" mail as well. To stop the 200 mails receive untill now, I blocked his mail adress on server. Our site and mails are hosted by Yahoo, NOT the free mail.
I still keep on receiving these 2 mails all the time. How is this possible. As it is blocked on server is should come from my own PC then.

Does anyone knows what is going on? Or give me some hints to come to a solution... Is it a virus? I scanned with AVG7 and I'm clean...

 

I have discovered the answer to my problem above. Both mails got stuck and downloaded all th time because this code never changed. I deleted them on server and the problem is solved.