hi there - i have just boght myself a bmw 535 and want a carputer

i have a laptop i dont use laying around and was hoping it would work

firstly i am in the uk and cannot use the mp3 store

can i hardwire it in how do i turn it on and ideally a single din 7" dash screen

laptop is p4 3ghz 512ram 80gb hdd ati graphics card 128mb

what do i need?

and best place to get it from not cheap chinese tat from fleabay