First off - this is totally at your own risk, will void your warranty and if you haven't soldered before don't use this as practice - try on something cheap first. Step 1 - Put laptop into service mode: Shut down laptop and disconnect from power. Then hold "B" down while you press your power button. When the dell logo comes up, press any key several times to enter service mode. You can now safely remove your back cover. Step 2 - Remove the back cover: Flip the laptop over and take all of the screws out - put somewhere safe. Then remove the back cover using your fingernails, apply gentle pressure and the clips will come loose. Step 3 - Remove the battery: Remove the screws holding the battery in place. Once they're out you can move the battery out of the way, you don't need to disconnect it. Step 4 - Clean a spot on one of the copper pads with fine steel wool (I did the one on the right as per the photo). It should be shiny and smooth when it’s ready, otherwise solder won’t stick. Step 5 – Strip both ends off a piece of wire (about 4-5cm long). Loosen one of the screws on the silver part of the touchpad and wrap one end of the wire around it, tighten the screw so it holds one end. Step 6 – Make sure the wire is long enough to reach the copper pad you just cleaned. Solder the second end to the copper pad. When soldering be cautious to not overheat the pad. I used a 400degree Celsius tip and it only took a moment before the solder melted. Step 7 – Once you’re done, reassemble the battery and back of the laptop. I found it easiest to put the screws in at the back corners first, then push the clips back in, then do the rest of the screws. To exit service mode: connect the charger and press the power button.
My Dell Inspiron 16 7610 started having shaky cursor problem a few weeks after receiving it. A Dell Tech came to house and replaced touchpad, he made it worse as Computer wouldn't even turn on after he was done. Very rude and in a hurry because it was late in the day, Sent computer to repair facility and same problem about a week after I got it back. Sent back again and the same problem happened. I called and talked to Customer Service and they agreed to send a Replacement which is a refurbished unit. But that is Dells policy since I had over 30 days. After 10 days refurbished unit started to do same thing. Now I have to go through same procedure again. I spent $1300.00 originally when I bought the NEW LAPTOP to end up with a refurbished unit that still has the same problem. 
Inspiron 16 7610 touchpad issue erratic cursor