If you have warranty and do not care about the data, get a replacement.
If you don’t want to go that route, the first thing is, you need to find out if you have software or hardware issue.
Also check this see if it helps you.
http://community.wdc.com/t5/My-Book-Live/GUIDE-How-to-unbrick-a-totally-dead-MBL/td-p/435724