3TB Mybook live - not visible on my network

I have 3TB Mybook live.  It was working fine, but one day it suddenly became not visdible on the network.  I have sone all of the obvious things like checked netwrok cables, reset the device (4 seconds on the button), repowered etc.  When I turn it on it goes from solid blue to solid green.  But still cant see the device. I cant even see it as an IP device. Any ideas on what I could try?

Have you tried connecting the My Book Live directly to the PC? Also make sure that the My Book Live is on the same Workgroup as your computer.