Touchpad Problem. Hi, I couldn't seem to use my touch pad. I could use the left click and right

Question

Hi, I couldn't seem to use my touch pad. I could use the left click and right click but not the scrolling. get what i mean? any ideas why? i tried uninstalling and re-installing the new driver but to no avail. Also, i just bought this laptop a week ago.. and it used to work perfectly fine the first few days until i start using usb mouse =X