Pls, my brother was working with a laptop and unknowing set d default program to windows media player. Ever since then have not been able to open any file on d system. I have tried to reset it using the set default program in the control panel but all is futile. The PC using windows 7 premium. Futhermore, all the programs is no longer displaying on the home screen. I av removed d battery and restart the PC d programs ae nt displaying. What cn i do?