I have an old notebook that somebody gave me. It came with XP Media center loaded on it originally. It still has the genuine windows sticker with the Windows SN printed on it. But there is no media with the notebook. I installed XP Media center from scratch using the Media center cd from another notebook. I installe dit using the original Microsoft SN, but the notebook would not activate so I activated it over the phone and everything seemed ok, but when I went to do the windows updates and installed the validation tool, I started getting a message that my windows was not genuine. Is it simply not possible to reinstall XP without the original media that came with the machine even if i have a legitimate Serial number??