Uncontrollable Screen Scrolling

I will notice that my mouse pointer will split in two and when this happens I know the screen will start scrolling very fast soon. When it does this I have no contol over and it goes so fast everything is just a blur . The only way for me to get it to stop is reboot and it may not happen again for a couple of weeks. I have updated the video driver , replaced the motherboard, palm rest , LCD panel,LCD cable ,LCD cover ( all replaced under warranty) . I have updated the Bios and touchpad driver , not sure what else I could do. Would greatly appreciate on any advice on a fix. Thanks!!