How can I back-up t my new 1TB WD Elements?

I have just bought a WD Elements (1TB) thinking I could back-up my PC on it, but there is no back-up software that came with? Which software can I use to back-up?

You can use the standard copy and paste method to move data to your Elements drive.  However, XP and above comes with their own backup utility.  You should be able to find it in the Control Panel.