abbeymoring

I opened an email from someone I knew, but it was a virus. It seemed like I was not able to open it, but then other people I know received emails from me, or people in my address book (and people not in my address book whom I have received emails from.) Each person has a different subject, but everyone (including me) who sends out a message has the words "Troy Ball" in the body of the text.
Any help is much appreciated. I know nothing about viruses, and I am also interested in finding out how to scan my computer.
Thank you!