Why is my C731T touchscreen no longer working?
If your Acer Chromebook C731T touchscreen is unresponsive, you need to update your Chromebook. Google has released a driver update in Chrome OS 91 to resolve this issue. Acer recommends updating your Chromebook to Chrome OS 91-13904.32.0 or later.
For more information on how to update your Chromebook, see How to Perform System Updates on My Acer Chromebook.