I learned my lesson the hard way too. I opened mail from someone I thought I knew, but it was someone with the same name, it was just missing one letter. Well, 500 bucks later, I'm wiser. I'll never do that again.

Patti

Never open any file from someone you don't know.

Even though the person knows me, I always make a comment in the text section of email that lets the person receiving any attachment I am sending know that it is legitimate.