Spammer Using My Email Address!

Strange but true! Your techs are correct when they say this is the work of a spammer, and it does NOT indicate any security breach on your computer.

Spammers generally don't like to poke their misshapen little heads out from under the rocks where they live, so they try to divert attention from themselves by making it look like someone else sent that "enlarge your body part" message.

It's trivially easy to spoof the From address in an email. In fact, most email software will allow you to change the From or the Reply-to address to whatever you want. Spammers use high-volume mail merge software that picks a From address at random from their database of addresses, and sometimes even the recipient address is forged.

The reason you get those bounce messages is because the spammers don't really care if some of their emails are sent to addresses that are invalid or defunct. It's all a numbers game to them. Some email servers are smart enough to look in the email headers and easily determine that the person in the From line (in this case, you) didn't really send the message. But others do not, so you get dumped on.

It's even worse when the spam *is* delivered to a valid address and that person blames YOU. In such a case, you can just explain that it was the work of an Evil Spammer who forged your address. If they give you flack, tell them to examine the Received lines in the email headers (most email programs let you view the headers if you poke around in the options) and they'll see that the source of the message was not your service provider.