It sounds like the first problem Azure is having is that someone has a virus on their computer. Many of the new email viruses will scan the infected computer for email addresses, including the address book and any email messages on the computer. It will then send an email to you from that computer, but will use a third, random, email address as the return address. Even if you don't know the person, all it takes is a friend of yours to forward the email on to them, and now they have your address somewhere in the message.
Something like this is happening to me right now, but the only thing I can do is make sure my anti-virus software is up to date. People with broadband internet connections should also use a good firewall (ie. not the one built in to Windows XP) as these can stop many of these viruses from sending out the emails if the computer does become infected. As viruses can spread too fast for the anti-virus software makers to update their software in time for everyone, a firewall will help alleviate the problem.
If you know the email address of the spammer you could just sign them up for catalogues, mailing lists and anything else you can think of. This has happened to some of the bigger spammers in the US. People got a hold of the spammers address and went to town with the subscriptions. Unfortunately it won't stop the spam.