I hope that any one can help me because Sony won't. I will be extremely grateful for any help. I purchased this computer 3 weeks ago and have struggled with this issue ever since. I received the computer with Windows Vista. I did the research before hand to be certain that I would be able to install Windows XP without losing any major funcitionality. According to Sony Support I would only lose camera funcitonality and possibly fingerprint scan. I can live with this. I have formatted this harddrive and installed Windows XP 4 times. I have downloaded all of the drivers and updates from the Sony site in the exact order they specified and still no luck. I have been able to get everything to function except for the power management. The fn keys work with all options except the brightness of the screen, which runs on the brightest setting all of the time. (works fine with vista) I am unable to change the screen brightness with the fn key and I am also unable to change it in the windows power management utility. It is bright all the time, while plugged in and on battery power. I love the notebook and I really want to solve this problem but the, sorry for your inconvenience, answers I have received from Sony, have me at my witts end. Their tech support are not tech's, they are $8 an hour people typing answers they find on a card. I am so frustrated and I need windows xp. I hope that someone has a possible solution, or I will be forced to try and sell this great laptop and buy one that comes with XP from factory.