Hp pavillon a1200n network problems.?

Hi i have a hp pavillion a1220n and i have recently been having some problems with it it was working fine and my internet was kind of slow so i switched internet companys and my other computer seem to be working fine with the internet but when i plug in the modem at the back of my computer it dosent seem to detect it i dont know what the problem is maybe its the drivers please give me the link for the necessary drivers.