What is a good,free software tool to automatically backup my PC data regularly to an external hard drive?

hotrod7262,you wrote

I want to be able daily backup songs, photos, e-mail to an external USB hard drive. So, I want a free tool that will do it automatically every night.

Windows OneCare live perfectly. Simply go to the home page of Microsoft and download it. It helps you back up your files and a bunch of other tricks to speed up your pc. So once you save a file, there would be no back again, in other words, it will only save the files are new, after carrying out the first