Why a generic microsoft driver would cope ok, I cannot answer. Several others have mentioned earth loops here and I agree with them and that the Alps software is getting overwhelmed. This suggests that the driver is being hit with a stream of random data (Noise) from the touch pad thus effectively locking it out. When you touch a metal part of the chassis like one of the two studs beside the docking connector, it will also work ok.Ĭuriously the screen pointer will occasionally change to a scroll pointer even when not touching the pad. Touchpad freezes when PS plugged in, everything good when running on batteries. Offshore on a vessel, I plugged the 4.6A power supply directly in to the laptop and suddenly found the same issues everyone talks about here. In the UK everything appears to work fine. I have a dock station with a third party (chinese) 4.62A power supply and the original Dell (Chinese) Power supply 3.34A. I have the ALPS Driver, I dont have McAfee or any other virus software installed. I have a new fresh Windows 7 installation. Some things which may help clarify the issue I am seeing. Just bought a second hand E5420 and lo and behold issues with non working touchpad as per this topic. I'm really not impressed with this laptop. I just hope it's not a crappy as the first one. I'm now waiting for a warranty replacement. Then, a few days later, it wouldn't even power on! The power light & the caps lock light up for about 5secs & the CPU fan starts then it goes dead again. It wasn't a problem with the button because if I did actually press it, the volume would decrease faster. The volume kept lowering itself a though the decrease volume button was being pressed. Anyhow, a few days later another problem appeared. The funny thing is that the diagnostic didn't show any problem (!?).

Release Fn at exactly same time as power button) & they came to the conclusion that it was a hardware issue. I contacted Dell Tech support & they suggested a few things including BIOS update & running a full diagnostic (with power off, hold down Fn key for 3sec and then press power button briefly. The touchpad worked for about a week & then, failed altogether. Things went from bad to worse after the promising 'breakththrough' I had with the docking station. Guys, just a quick update on my situation.

Dell 5420 driver