Backing up the information that you store on your PC is crucial to prevent data loss if your PC breaks. Although Computers are very reliable you can never tell when one will fail. I have known PC's to run with no problems for over 10 years and yet others have had problems after just 12 months.
There are two relativley inexpensive ways of backing up your data.
1 - Buy an external hard disk. This device plugs in to a USB port and usually comes with backup software that will backup the data you specify.
2 - Use an online backup service. These services run in the background automatically backing up all your data. The service I recommend is Carbonite. I have been using this service for over two years without any problems.