I have an Inspiron 6400 w/ ATI X1300, dual booting XP SP2 and Vista Business. I am encountering this issue in both OS environments. When I'm using the laptop normally, my touchpad works perfectly. However once I connect it to a TV and set it to dual displays (FN+F8), the touchpad behaviour becomes erratic. When trying to move the mouse, it will randomly click even if my finger is completely depressed onto the touchpad surface. If I disable tap-clicking then the erratic clicking stops, but this isn't a viable solution as I would have to keep turning this on and off every time I use video-out. I've tried uninstalling the ATI drivers and Synaptics drivers with no success. I've also tried upgrading both drivers with no success. I just installed Vista fresh yesterday and the problem still persisted with both the drivers on the Dell cd that came with my laptop, and the newest drivers found on the Dell website. Any help or direction would be greatly appreciated.