Its an email virus... Many e-mail viruses now use random e-mail addresses from an infected computer's address book in the FROM and TO fields of messages the virus sends. Most likely the virus on someone else's computer has found your e-mail address in an address book and used it in the FROM field as the virus replicates itself via e-mail. The messages look like they came from you, but they did not. This is called e-mail spoofing.