Not as simple as it says on the box
Was on Vista. Saved my important docs, picture etc. before starting although it said it wasn't necessary as it kept them. It refused to download using 'Upgrade', aborted 3 times. It said certain computers could not be done this way, so had to use 'Custom'. Lost everything then, I Tunes, all drivers, Norton, E Mail. Good job I backed some of this up before I started. Took several hours to replace everything. This job is not for the faint hearted!.