I noticed an odd server in the left hand column of Finder, seeing as I've not got a PC connected to the network I chose to take a closer look. According to my router's log, a new IP (...2.7) logged in around the same time, so I assume someone has managed to crack my WPA password (considering it's random, that might show serious effort and intent was involved) or there's a blindingly obvious innocent explanation that I'm not seeing. Due to this happening, I started to secure the network, but when I tried to turn off File Sharing on my iMac I was given a warning that other users may be logged in. Could this mean that someone could have cracked both my WPA password and my iMac's password (different, but again random letters and numbers) or would it just say that even if they just got as far as the Drop Box? Any help would be appreciated, thanks.