You heard it many times, that you have to backup data. It's not needed till the first crash and all your work is lost.
All of the backup solutions below are free and you only have to download and set it up to start making regular backups, that can even be automatic.
Hard drives fail, it's not about 'if' but 'when'!
And when something happens (crash of your disk, virus, your computer gets stolen ...) you can restore all of your data in a short time from the external drive, tape, DVD, cloud backup or zip file. Choose a free backup software from the list and start protecting you against data-loss today! And don't forget to try restoring your files from time to time, to be sure ... ;)