Hi,
I have the same issue as a lot of people here, that the cursor gets stuck in only up down movements quite frequently when in use and the cursor movement becomes erratic. This was ok for the first 2-3 months of use but happens virtually every time I use it now. I believe it's a hardware issue as I have noticed that every time I tilt the laptop to one side (originally 20 degrees or so but now 35-45 or so), it resolves the issues. I saw someone on another thread mention that they had numerous replacement part but it's to do with a faulty wiring issue that causes a cable to get trapped near the touch pad and affects it picking up the signals when lying flat. I also noticed it will only work when tilted with the right side higher.
http://www.daniweb.com/hardware-and-software/pc-hardware/usb-devices-and-other-peripherals/threads/348044/please-help-dell-inspiron-14-touchpad-problem
I'd like to have an engineer come out and fix this issue as most threads show that driver and part changes have no effect on the problem.