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?
First do try to uninstall and reinstall the keyboard driver in Device Manager. Once the keyboard driver has been removed reboot the laptop and it should reinstall automatically once rebooted. If that doesn't work please do run Windows update as there might be an update available for your keyboard. Lastly do run a virus scan with your laptop as it might be infected and which is causing that problem to happen.