I have one imac (running leopard) and an oldish macbook (also leopard) which can 'see' eachother as soon as the macs are switched on. However my newer macbook Pro (running snow leopard) can't 'see' the other two. They can find it but it can't find them. Can anyone help me, in idiot proof terms to get my macbook pro connecting to the other so I can share files? Thanks!