I have a Toshiba Satellite C875D-S7120 to fix. It has Windows 8. The touchpad and mouse buttons do not respond at all. They quit accepting input without warning. Device Manager and msinfo32 show no errors and Device Manager says the device is working properly. I have tried the Fn + F5 to turn off, then back on, and that has no effect. I tried 2 older drivers. Both installed correctly but did not fix the problem. I have 3 spare scrap Toshiba Satellite laptops, a C655-S5225, a Pro L550-EZ1702, and a C855D-S5305. All 3 have the same Synaptics touchpad, the part numbers match. I swapped in each of them and tested. That still did not solve the problem. Is it maybe a problem with the touchpad connector on the motherboard? The system is otherwise fine and works properly and a USB mouse works.