My wife's Dell Inspiron had such severe touchpad movement issues we were at the point of scraping it as unuseable. The cursor arrow would randomly stick, jerk instead of moving smoothly or fly across the screen. I tried re-installing the touchpad driver - to no avail.
Then I came across this old post (old enough I had to start this new discussion) from Kelly that solved the problem. I would never have diagnosed the issue so well and am re-posting the solution because there must be thousands of very frustrated Inspiron owners.
I was having strange issues with my trackpad on the Inspiron 14z too. At random times it would freeze up and only allow vertical movement. The tray icon during these times would show that the trackpad was receiving a great deal of pressure, even if nothing was touching it. I uninstalled and reinstalled every driver I could find... to no avail.
Eventually I was able to deduce that the problems were correlated with having pressure below the trackpad, like if you were holding it on your lap, a bed, or any other soft surface. Finally I got fed up with it and decided to open up the bottom since it definitely seemed to be a hardware issue. If you are comfortable working inside your laptop, or have a friend or family member who is, here are the steps I went through to resolve this problem.
Make sure the laptop is completely off, unplug it and remove the battery to be safe.
Flip the laptop over and locate the removable panel in the bottom right. There is one screw in the very bottom right corner to remove. It doesn't come all the way out of the plastic. Once it doesn't seem to be unscrewing anymore, use it to pull the plastic up and unhook the whole panel. You may need to use something to help you pry it up. You don't have to use much force but it's tricky to get it started.
Once the panel is off you will see the hard drive. There are 4 screws holding it in. Remove these and set them aside. (David – don’t make my error of mistaking the 4 screws holding the circuit board with the correct 4 screws holding down the hard drive)
Slide the drive and its enclosure to the right in order to disconnect it, then lift the enclosure out.
Now you should see the culprit: the hard drive ribbon cable is hanging right above (or below, depending on perspective) the trackpad. If you peer in there with a flashlight you can see a black square in the center of the trackpad that the ribbon is practically touching. It's easy to imagine how pressure under the computer could cause this cable to touch the trackpad and make it behave erratically. It may also happen if the drive is working particularly hard, not sure.
(David – it took me a few minutes to find the black square. It’s small – by ¼inch by ¼ inch and directly under where the cable makes a 90 degree turn travel across where the hard drive was before you removed it)
Anyway, we need to get this cable out of the way. I got a small piece of Scotch tape and pulled the cable firmly to the right. There was a fold in the cable that made it hang down from the drive connector at a right angle and touch the trackpad. Pulling it to the right eliminated this angle and shifted the crease to the other side. I taped the cable in place and pressed firmly on the tape to make sure it was not going anywhere.
Slide the drive back into the connector, put the 4 screws back, and reattach the panel.
As I type this I am holding my laptop on my lap and having no issues. I haven't had it act up once since I did this, even after testing it with all the behaviors that used to trigger an "episode". I hope this can help someone else who has felt like throwing this laptop out the window a few times!