Force MyBook to not sleep?!?!?

Hey everyone, I just want to ask if there is a way to make my Western Digital 500gb MyBook to not go to sleep. It's really annoying because every 1 hour time machine has to back up and i have to hear my hdd rev up and theres a "minor" slowdown on the machine. Also, my itunes library is located on the mybook so i hate to have to keep making the drive spin up and down all the time. if this involves terminal, i just got a mac a week or so ago, so i will need step by step help.

Hi. Try going into Apple Menu>System Preferences>Energy Saver and set sleep to never. Does that help? Good luck.