MSN Premium eMail

I have MSN Explorer from Qwest. Somehow MSN Mail has been set as ny default
mail client. When I try to send an email while online (I was trying to get
info from a Craigslist advertiser) it tried sending the email using MSN Mail.
Since I don't use MSN Mail (I use the email that comes with MSN premium) it
asked to set uo MSN mail. I couldn't because I dont have a POP 3 account. Now
I feel like Paris Hilton in an LA Jail. How can I change this so I can send
email responses without MSN Mail getting into the act? I can send and receive
"regualr" emails just fine. Thanks.