The easy button would be to purchase and setup an online backup solution like Carbonite (www.carbonite.com) or Mozy (www.mozy.com), there are others also, a link to reviews from PC Magazine is here http://www.pcmag.com/article2/0,2817,2288745,00.asp.
The simpler way, without costing too much upfront would be to go and purchase an external USB hard drive. Base the size off the total amount of storage that you need to backup, and then go with the largest drive you can afford. Plug that drive into your “server” or desktop and then simply setup Windows Backup, which is a built in backup solution in the Windows Operating system. That solution will allow you to do a bear metal restore onto a new computer if you need to. It will also allow you to select the files and folder locations that you want to backup, how many copies of the backups to keep, and for how long. This basic solution is much better than doing nothing at all. A guide to setting up windows backup can be found here. http://windows.microsoft.com/en-us/windows/back-up-files#1TC=windows-7