That is probably just "spoofing" Rosanne. Everybody gets those, just delete them without opening them and keep doing your virus and spyware scans as always. It might not be a bad idea just to be on the safe side to do a TrendMicro Housecall scan for a second opinion though. It takes a little bit of time depending on your connection speed and computer specs but it's worth it for the piece of mind. This is the link, hope this helps. It's free.
I have been receiving "mail delivery failure" when I check on the reason it is not anyone (email address) that I have sent anything to. I have noticed that this email address is from a friend of mine who forwards to me. In front of the returned email address are "3d". Is this a virus or worm? How do I stop it? I probably have infected my friends because of forwarding emails. I also have been getting reply emails w/no name or email address. I have not opened them up to see what they contain. Any ideas? I have adaware, spybot search & destroy, AVG., Zonealarm.