Sorry, i don't know how to describe for more detail. But I will try it. For example, when I use microsoft office word or power point 2007, it is often and repeatedly my screen will freeze and I cannot move anything although the mouse. All operation in that time will stop working, the screen will freeze. It will remain freeze about a minutes. At the same time, the light symbol harddisk will light up continuously. After that, it will come to normal again. The light symbol harddisk will not continuous light up and microsoft office will run like a normal. It also will occur when I surfing internet and playing games. The screen will freeze and all running program will stop working for a moment, the light symbol harddisk will continuously light up until all program running as normal