Comment 65 for bug 1258837

Might be related to Lorenzo's thought: the random jumping and clicking only happen when the touchpad is treated as touchpad. I haven't had any problem when loading the touchpad driver as a simple mouse (no scrolling, tapping, multitouch, ... for the touchpad):

sudo modprobe -r psmouse
sudo modprobe psmouse proto=imps

I also found that whenever the touchpad started behaving badly (lots of "lost sync" messages), reloading the driver seems to reset it back to be good for a long while:

sudo modprobe -r psmouse
sudo modprobe psmouse

About keyboard input, it might be hardware (pretty common for Dell). I have an E6440 that I can easily reproduce the key repititions by hitting the keys in a certain way (e.g. tapping a key straight down lightly while relaxing my finger). It looks a lot like the "bounce" effect in the old desktop keyboards, perhaps Dell didn't put in good-enough bounce-filtering. I can reproduce the same problem in Windows and FreeDOS. My E7440 also had that problem initially (although not as easy to produce as the E6440), but not after Dell replaced the keyboard (together with the touchpad).

One solution for the keyboard repetition is to set the Bounce rate: Universal Access > Typing > Bounce Keys > Acceptance delay. You will have to experiment to find the right rate that work for you without missing intentional repetition (especially when smashing the keys when playing games). What works for my E6440 is to drag the delay all the way to shortest, then move the slider to the right (long) twice using the "right arrow" key.