My Book Essential Shut Down!

I was trying to retrieve some information from My Book Essential, which I had never done.  I have a 2006 Mac OS X)  In the middle of trying to do that, I was told there was an update and I should do that. When the update was done and I had restarted my computer (as it told me to do), the drive lights went out and the icons for the drive and the SmartWare were gone off the desktop.  What happened?  How do I fix this.  Please take in mind I am not computer literate, so please,  please be very clear about your answer.  Thanks SO much!!

Forgot to add that I am running Snow Leopard.