Western Digital Backup Software Using My Western Digital External Drive?

Using my Western Digital external drive? - western digital backup software

I recently purchased a 750 GB Western Digital My Book Essential Edition external hard drive. The instructions I had to plug-and-go and when I did was to use BSplayer. I started to backup all my files and had no problem. Later, when I went to store additional data, said test my software has expired and would be a product key that was not foreseen, and for a price of $ 49.99 must be purchased. Can I still install without using the backup software or do I put in the money?