how do i install xp on my packard bell?

i brought a packard bell about 18 mnths ago which came with vista pre installed. how can i delete the hard drive or wot do i need to do to completly remove vista to install xp! the xp disc just keeps giving my an error wen i try to install it over vista! and i was told that my motherboard was only designed for vista hence the reason xp wont install! is this at all true, if not how do i acheive the goal of installing xp and complketly removing vista?