If you’re upgrading a computer running Windows XP, you can save money by opting for an upgrade rather than the full version of Windows Vista.
However, you can’t necessarily perform an ‘in-place’ or ‘over-the-top’ upgrade; sometimes you have to perform a clean installation of Windows Vista, which means backing up and reinstalling all your current programs, folders and files. The table shows where an over-the-top upgrade is possible.
In practice, a clean install means a fresh start; anything short of this can carry over problems from your old, cluttered version of Windows XP. Strictly speaking, when Windows Vista installs itself over Windows XP, it actually does perform a clean install and then imports all the old settings.
This should help prevent problems and can even, in principle, carry through hardware drivers that can’t be installed under Windows Vista itself, thereby preserving the working life of older devices. However, we’d recommend a truly clean install whenever possible. More »