A note that this does not back up the operating system and will not get your computer running again. For that my computer I have a RAID 1 system. This means that I actually have 2, 500MB HDDs in the computer that are duplicates. If one of these drives fails I just need to swap in a new one to recover. Granted, this is a little over the top for most people, but I use my computer for work and the work I do requires that I can recover from anything that might happen. To be honest, getting a computer with RAID 1 is not very expensive if you get it built in, but it is something that you have to look for and cannot usually added after the fact to an existing computer, at least not as cheaply as getting a computer that has it in the first place.