I have a toshiba l775 -12v and this solved my problem : https://www.youtube.com/watch?v=8LnNsiJE2Mk
Synaptics Pointing Device Driver: http://drivers.synaptics.com/Synaptics_v19_0_19_1__C__x86-x64__Win10__Signed__MS_Win10_UXUI_PS2_SMbus.zip
best regards