If you have not already done so, you might try sending the user a personal message. Since there's been a long time lapse between the posts, there's a good chance that this user is no longer an active reader of these message boards. However, if he/she did provide a valid email address, which they check regularly, then a copy of the personal message will be sent via email also (as long as this function hasn't been disabled). Of course, this is based on a variety of assumptions, but it's worth a shot, if you have not already done so.