Just ignore it.
Most likely, someone you know who uses Windows and has you in their address book has an email virus, and it's sending out messages with you as the From: header. Note than in internet email, there is absolutely no intrinsic mechanism to prevent you from putting any name next to any email address on any message. (Some smarter mail servers prevent this, but viruses generally provide their own mail server, which obviously is not encumbered with security.)
tooki