I've had my Macbook for about 2 years now. This is the first time I've had this problem. My cursor will move around the screen when I move it with the trackpad or an external mouse, but when I use my left mouse button or the mouse button on the laptop, the action doesn't receive and I can only right click with the external mouse. Is there any way to fix this problem and get my left-click working again? I'm running Tiger with a 250g hard drive (Which is a replacement for my previous 50g HD which failed on me).