Lose access to internet after adding my book live to my home network

My home network consists of a dlink DSL2730B adsl modem router, a Windows XP desktop, a printer, and wireless access via the router. It has worked fine giving me access to the internet. I do 90% of my internet access from an Ipad2. I recently added a My Book Live connected to the router, and it s visible on the network, and i have backed up my desktop to it. However within about 30 minutes of connecting the My Book Live I lost connectivity to the internet. Everything else is working, i can see the mybook from the PC. This has happened considtently every time i power up the mybook, so that i now leave it unpowered unless i want to use it specifically to store or retrive something. To get internet access back i havevto power off the my book, and cycle the power on the router. Can anyone suggest a solution ?