Can't turn off touchpad!

Hi and thanks, but no, I have no Dell option in Control Panel or anywhere else. I also looked at the mouse settings but there's nothing there. I should add that after reboot, when I bring up the Touchpad menu in settings, under Touchpad Settings now, the only option is Touchpad sensitivity (the option to turn on or off is gone). 

Have you looked in Control Panel? There may be a Dell touchpad program in which you can toggle off the settings. My E5430 had a similar problem until I changed the settings in Dell TP app.

Have you tried disabling the touchpad via function key? On my old Dells I can disable/enable the touchpad via F3 + modifier key (or F3 alone if the modifier/media keys are set as default behaviour in BIOS).

Please press windows key and X key at the same time, click Mobility Center,and then Turn off touchpad.You can also disable touchpad by typing device manager onto (Cortana)search bar, expand Mice And Other Pointing Devices, right click Dell Touchpad, and then disable.

You need to maintenance.

There is no such option there and as I already explained, I did disable it in Device Manager.