Just to inform those of you who are unaware of the procedure of activating your OS if, when re-installing, you find that you have exceded the amount of times you can re-install, as I did. Just call the UK telephone number that is displayed in the dialoge box that appears, and hopfully as in my case you will get to speak to someone, you will be asked for the activation code which is displayed in the dialouge box. You will then be told to type into the available boxes a new activation code. All of this took less than ten minuets to complete. All very easy. Hope this information is useful!