did not know you could download Norton Ghost 15 from Symantecs site, is this where you got it? Otherwise... if you bought it online and/or a store, NG15 is a physical box, with physical software, meaning, a physical disc, which ISyour bootable media.
NG15 has no volume license methods as SGSS does... it is a box only product, simple to use; it says what it does and it does what it says. There are plenty of sites that have step by step instructions on how to create bootable usb flash drives for ng15 (and previous versions) since youre on a netbook.