How to backup files with a software.
If you do not want to backup the entire hard disk but only a few files etc., do it best with a backup software.
You can use a CD / DVD or a memorystick.
I use almost only freeware and here is a good program for the PC.
http://www.cobiansoft.com/index.htm
And here, one for MAC.
http://www.grapefruit.ch/iBackup/
If there is someone who have a better software tell us.
But remember it must be freeware.