I bought a non upgrade Windows XP Pro SP2. I installed it on both a desktop and a notebook. I purchased a new desktop. I intend to install the XP Pro over the OEM XP Home that is pre installed on the PC that was just bought. When I register the XP Pro, will microsoft tell me I am installing the XP Pro on an additional PC and require me to telephone microsoft and explain I am installing the operating system on a replacement PC rather than another PC? I reinstalled the OEM XP Home on the older desktop PC.