2 Answers

Instructions with pictures >> http://www.wikihow.com/Back-up-a-Computer 

------Decide on the proper backup media for your needs. CD-R, DVD-R, tape, hard drives (internal or external), online, and flash drives are all great choices, but the right tool for the job is always best. Do some research on the advantages of each, and choose the one which will best suit your needs

--------Choose a backup application. For personal computers, there are many options.

• If you are using Microsoft Windows, there is a backup application built in (Start>Programs>Accessories>System Tools>Backup). If you use Windows Vista, go to (Start>Control Panel>System and Maintenance>Backup and Restore Center). You can also use third party back-up managers, ranging from small programs to full online backup services.
  
   
  
  


• Mac OS X has the Time Machine backup application built in.
  
   
  
  


• If you use a flavor of Linux, there are many open source options available in repositories for all of the major distributions.