Blocking an email address or a sender in Windows Live Mail is easy.

1. Open up the Windows Live Mail program.
2. Right mouse click on the email you want to block from the 'Conversations' list.
3. Select 'Junk Email'.
4. Select 'Add Sender to Blocked Senders List' to block that email address from emailing you again.
5. If you choose 'Add Sender's Domain to Blocked Senders List', any email sent from that domain will be blocked. This is a good way to prevent someone from creating multiple email addresses in order to surpass previously blocked email addresses.