I thought someone might be able to shed some light on this. In my sidebar I noticed that there is a machine logged on that I do not know or maybe understand. It is named imac-a350f6, i believe that the last six numbers have something to do with the machines MAC address. It doesn't match anything i own. So, last night i logged into my airport extreme, the newest one, and set up the MAC address access control. I set it to timed access and inputted everything that i own and gave those things unlimited access, then I set the default to no access. Tonight the item is back in my shared section of my sidebar. FYI it says it is a PC Server.