Hello,
I'm also needing the same driver (UJ850). I've installed the Windows Vista Ultimate OEM Dell Version. During the instalation, the DVD drive worked normally, but after the finish of setup, the Windows Vista doen't recognize the DVD Unit. There's an unknown device on Device Manager, but i don't know if it refeers to DVD Drive. Therefore, it works fine on Windows XP. Only on Vista version the problem happens, and it's driving me crazy. Please, I need some help.