e-mail with frames

Hi all, question here. I received an e-mail from a DG member that I don't think I know. subject: How are you. It said it had frames and only open if you trust the person it was from. There were 2 attachments listed but I didn't open them. What are frames in e-mail? I really don't like to not trust, but I'm afraid if I do trust everything that shows up in my e-mail I will get a virus or something. I did send the sender an e-mail to see who it was and that I didn't know what frames were & wouldn't open their e-mail until I knew. I hope this is not being rude! thanks for any help you can provide on this. Julie