Network security map

First of all i am very new to computers and if anyone knows the answer please can they explain in great detail!

First of all a friend of a friend installed my belkin wireless router for me for my laptop. I don't have any other laptop computer in the house. I then installed norton myself. When i finished installing it (about 3 months ago now) i noticed when i go into network security map it says my network connection is not secure in red. I did find a link on this site about encription but don't have aclue where to start even though i watched the tutorial. Can someone please help. My last question is when i logged on today to my network security map next to my pc picture at the top with my name was anoth pc saying new i have not added another computer, is that what it cound be because my network is not secure. When i clicked on it tonight it say offline.

Very confusing.

Please help:smileyindifferent: