I dont understand :'(

Hello,
i understand a bit about computters but not much, i have my ps3 nere my computer and i have clicked my ethenet cable into the both of them. my ps3 was conected to my internet before but now for some reason it isent, i have realise my local area conection is missing from the bottom of my computer screen, i know kind of how to creat a nother one but it keeps asken for an adress and i dont know what to put there and my ps3 keeps asken me for my dns server how will i fix both of them problems ???????????