A good backup policy is essential to sound data security, but as well as copying important files to a secondary drive, you should keep a copy of your entire operating system. Should you have a drive failure, you can then resurrect your complete software platform onto a replacement drive, with the minimum of effort.Under Windows XP, you would have to use third-party software, such as Norton Ghost or Acronis True Image to create and, if necessary, restore an image of a complete drive. With the Business and Ultimate versions of Windows Vista - though not with either of the Home versions - this facility is built into the operating system and is called Windows Complete PC Backup.
You can create this kind of image on a second internal hard drive, a plug-in external USB 2.0 or Firewire drive, a DVD rewriter or, at a pinch, on a secondary partition on your main hard drive. This last option isn't recommended, though as, if your hard drive crashes, you're quite likely to lose all the partitions on it, including any backup image.
Drive images, even when compressed, can take up considerable room, so even a rewritable DVD is not a great solution for backup, as it will require several discs to store even a modest system. A secondary hard drive of some sort is the neatest, and quickest, solution.
How regularly you make a drive image is up you. If you buy a new PC with Vista pre-installed, or are about to upgrade, it's a good idea to make an image as soon as possible, so you have a 'clean' system you can revert to. It's a good idea to create a new image each time you install a Service Pack, too.
Making a drive image is not the same as backing up individual data files, as with a drive image all the applications, system files and registry details are also copied. It's not the same as System Restore, either, which reverts a system to an earlier date, without disturbing data. When you restore a drive image, it overwrites the entire contents of the drive: system, applications and files.
