Touchpad doesn't work on HP Elitebook 840 G1

[MOUSEPROBLEMSSS]

I've been having a consistent problem with my HP Elitebook 840 G1 where the touchpad won't work.) Restarting did the trick once, but it hasn't since. I uninstalled the touchpad and reinstalled from the BIOS menu as I've seen recommended in other threads here, and it seemed to do the trick. However, this eventually stopped working.

I did not accidentally turn off the touchpad by double tapping in the upper left corner. I made sure of that (I did it once, and since then I've been sure to check I didn't accidentally mess that up.)

[banhien]

@MOUSEPROBLEMSSS 

Please perform a CLEAN install of the following latest driver

   https://ftp.hp.com/pub/softpaq/sp91501-92000/sp91562.exe

The package contains the Synaptics Mouse driver. The driver provides advanced features such as PalmCheck, EdgeMotion, tap zones, double-tap, and tap-to-select. This package is provided for supported notebook models running a supported operating system.

Hope this helps.

Regards.

[MOUSEPROBLEMSSS]

What exactly do you mean by "clean install?" I uninstalled the touchpad, then installed the driver you linked, and it still doesn't work. Is that a clean install, or did I do something wrong?