Here's a tip that might be helpful occasionally. If you receive an email that, for some reason, looks a bit suspicious, or has an attachment (a possible source of a virus) you can find out who it's really from by clicking "show original" per the instructions in the following link: http://www.isipp.com/resources/email-headers/
The instructions vary, depending on which email client you use. I checked this out in Gmail, and it works. This could save you from getting a virus from opening an attachment in a suspicious email.