On an older laptop Acer Aspire ES1-512 the touchpad is not working after clean Windows 8.1 Pro (re-)installation.
Things that could play role here:
Right from the beginning of Windows 8.1 Pro installation USB boot (UEFI mode) the touchpad does not work.
After the installation finished, I merely thought I'd install missing drivers with Driver Booster or similar tool, did not help.
There are yet about 150 updates available, none of which has Synaptic or Elantech in its name, (and I don't want to linger for hours just waiting).
If I unattach my USB mouse I see no pointing device in the Device Manager, it's not only disabled, it's unrecognized probably.