MilesAhead Computer Based Solutions suggest a multitiude of Backup Strategies to ensure your data, documents, photos, videos and music are safely backed up.
1 copy of a file is NOT ENOUGH.
A good idea for starters is to purchace an External Hard Drive. These are widely available.
Off Site
Dropbox offeres 2 gigabytes of free storage and is perfect for files you use all the time or for your latest project.
Free file syncronisation software is available for both Mac and Windows.
Select an operating system below to be taken to free download links for software.
Mac OSX: iBackup
Click HERE to Download
Windows: SYNCTOY 
Click HERE to download