You provided so little information that no one could make sense of this. Was the network wired or wireless. If wireless then you really would be unimaginably stupid to have it unsecured. If wired then someone was completely stupid in not knowing the difference between accessing wired and wireless networks.
Des
The original 32 bit junkie now snorting pure 64. BT Yeehaw! 8 Mbit BT Homehub2, Wired, Wireless, VoIP, 2 Macs, 2.5 Hackintoshes, 3.5 PCs, OS X, Win XP, MCE, Vista, Ubuntu.
Rehab is for quitters