Not having internet connection

Hello, I bought the new program windows 7 and took out vista, because I never like it. but after instolling the new windows 7 i cannot connect to the interne. I have a network in the house and when i check whta is the problem it say that my IP adrress is incorrect. I checked all my other network in the house and all of them are working. can any one tell me what I can do to fix this.