Two computers came in today with similar issues. Both dealt with the touchpad. In both cases it had just stopped working. Both of these computers were Toshiba laptops. One was a windows 7 machine that had been upgraded to windows 10 and the other was a windows 8.1. On the Windows 10 install the issue was two-fold. In both machines in the bios settings the internal touch device was disabled. On the Windows 8.1 this solved the problem. On the Windows 10 install I had to also turn off the EDT touchpad software.
Why is this unusual? Both units were brought in on the same day, both were Toshiba laptops. Both had the bios setting for the internal pointing device off. With that bios setting the touchpad should never have worked, even if the software drivers/control software for the device tried to turn it off. Essentially, nothing should override the bios settings. And no windows update should alter the bios settings.
Both of the devices were from different manufacturers. One was from EDT and the other was from Synaptic.
So, if you have Toshiba laptop and you have a similar problem where your touchpad just stopped working in the past several days, it is likely due to this.