Can't access My Book without reformatting

I have used my Mybook essential for quite some time.  Unfortunately, now whenever I connect it to my computer I am informed I have to format it before it can be used.  I don’t want to lose my data so what do I do?

Same thing happened to me just now. It says the drive is inaccessible. The virtual CD with the WD Smartware on it is working, but not where all my data is. If I lose all my stuff it really is going to hurt. I am open to any ideas how to save my data.