I have a Latitude CPx and experience the same problem. The tap to click is active on the touch pad and I have a heavy touch. This results in highlighting text, dragging objects where I don't want them etc. Download the Synaptic driver from
http://web.telia.com/~u89404340/touchpad/ and install. I am a newbie, and am still trying to make the driver work. The driver installed but needs configuring to turn off the tap to click. When I get it figured out I will post back.