How do i get my old itunes off of a hard drive?

i have an old hard drive with my old itunes on it with my old itunes library from an old windows xp computer. I have a new computer with windows 7 on it, so i have no use for this harddrive anymore, accept for the songs. do i need to plug the harddrive back in to get the songs or is there an easyer way to do it? also how do i pulg it back in and if i do will everything i had before work like the whole xp and everything else, or can it hurt my computer? Or is there nother way all around this? help!! thanks