I have had a Dell Latitude E6430 with Windows 7 for almost 3 years and for most of that time I have had a problem, when typing in word documents or in emails with the cursor jumping randomly (either many characters to the left, or up 1 or 2 lines or more) whenever I type a vowel, most commonly a or e. I'm certain it is not a mis-typing problem. Is there a way of stopping this?