How do I stop people next door accessing public folder

I have only had My Book live a few days but just realized anyone within range can get into

the public folder and copy or delete files.

I went on my kids windows 7 netboook,done a network search,

the computer found My Book Live,I clicked on the icon which came up

with an install option which I did and I now have full copy and delete options.

What stops the guy next door deleting all my public files or stealing my music.

Will have to stop using the public file.

I have found no option to protect my HDD for anyone within range of picking

up the signal.

Use the router to stop them.

1.  use a “password” for wireless access, e.g. wpa2 encryption

2.  don’t broadcast the ssid.

See your router’s manual & settings for info.

Of course ,it is plugged into the router.
Thanks for that.
I am protected but was thinking it was
Outside the network but it is not.