WD software problems

I backed up everything onto my new WD hard drive. I just plugged it back into my computer and now everything is missing and my new Macbook Pro isn’t recognizing the hard drive. Also when I plug it in it makes my Mac beep over and over again and allows me to do nothing unless I restart the computer. What is going on and how to do I get everything back?

Here are a couple of questions to bet asked so that we can help better assit you.

What is the model number of your unit?

what OS are you runing 10.4 10.5 or 10.6

is this a laptop or desktop