latitude c-series? if so this is a common problem with the trackpoint in the center of the keyboard (and/or the touchpad).
sometimes you can remove the keyboard, move the trackpoint 360' a few times, flex the keyboard a little (sounds nuts but it works) and then remove the "pencil eraser" tip to the trackpoint and it will stop after re-assembly. most likely cause was that clearance between the lcd panel and "eraser" tip was not enough, and lcd presses on tip, causing malfunction in the trackpoint.
you can remove keyboard by loosening all screws marked "K" on the bottom, then gently prying up the plastic cover strip over the power button, pull the KB loose, and (gently)disconnect the ribbon cable. there is a small plastic catch that must be slid up a little to loosen the ribbon.
also, you can download the synaptics software and disable the trackpoint in the software, which gives the cursor back once at the login screen.
last, if still under warranty, have them replace the keyboard.