Ask him to go for online chat with HP customer care...............one of my frnd also had this issue......his lappy is HP too.........
first we tried to do it ourselves.........but were unsuccessful............then he chatted with HP customer Care and asked about downgrading...........they told that they are not officially helping him............and sent some driver links to his mail........
but he couldn't try them as he had exams next week.......(so can't help u with d info, if the drivers actually worked or not)