Touch pad on laptop does not scroll without grounding
I have Dell XPS-14Z laptop with a Synaptics touch pad V8.1. The touch pad is giving me a trouble. When I have the laptop on the desk and I place my finger on the touch pad, does not want to move the cursor. When I have the laptop on my lap, it works fine. Also, when on the desk, if I hold the laptop on the left side next to the touch pad, or place my hand underneath the laptop, the cursor moves fine. the buttons work ok at all times. Works fine with a mouse. So, I conclude, the touch pad needs some sort of grounding to work. Please help - what could be the problem?