http://usermanualworld.com/wp-content/uploads/Dell%20XPS%208300%20Manual%20Download.pdf
Do Save as or Save Link I dont have dell or an XPS so i wouldnt know just trying to help
Hey guy i over looked this thread and i found out what it was that kept changing the brightness on is own.
http://www.eightforums.com/tutorials/6042-adaptive-brightness-turn-off-windows-8-a.html
Step One
Step 2
Step 3
And Boom It Should Work