The internet issue is likely an HP problem, do some research and you will quickly learn that HP builds HORRIBLE computer's. Ever since they merged with compaq, they've been having serious quality issues. (I've got friends with HP computer's, and i've owned a few to know first hand it's the hardware.)
I could go into detail, but most of you wouldn't understand my technical rants.
Play modern games, and you'll learn that Vista BLOWS XP AWAY.
theres a petition to save xp. i personally like vista and havent had problems with it, and im sure if u cant connect to the internet its not a vista problem. check your motherboard and ports on your router/modem/tower