How do you relocate iTunes to a new hard drive?

Our Number 1 son has just asked me this question and I have no idea what the answer is.
He says that he has iTunes on his computer but that his hard drive is now to small and he needs to change the hard drive for a larger one. His computer doesn't give him the option to fit a second hard drive (my first answer to him) and he doesn't want to go down the external hard drive route (my second answer to him) For some reason, he wants to just hook out the small hard drive and put a much bigger one in its place. He knows that he will need to reinstall all his software but that doesn't seem to bother him just so long as he can get all his iTunes stuff transferred to the new drive,
Is it possible to do this?
I don't even have iTunes myself but he says that you can't just copy it all to a pen drive and then copy it back into the new hard drive. (my third answer also shot down in flames)

Any ideas gratefully received but please try to keep it simple. Neither of us are any better than beginners at this computing malarkey.
Cheers,
Steve

Please read the following Apple KB article for instructions. LINK

Thanks very much for the link.
I'll pass it on, pretend that i found it myself and score some Brownie points, lol
Cheers,
Steve