Help.. to find out who sent me e-mail

I need to know how I can determine where an e-mail came from. I know about the ctl then F3, in outlook express, and that is what I have. However, do not know how to read it and do not know if it can tell me where it came from. Can anybody out there help me? This was a stalker… who then started sending e-mails to freinds. It came from a made up YAHOO acct.
Please help me if you can. Any advice would be greatly appreciated.
Thanks.