Either a keyboard or cable fault.
You MAY get lucky ree-seating the cable(s)
This has some hints and a link to a video
http://community.acer.com/t5/V-and-VN-Series-Laptops/Can-you-replace-the-keyboard-on-Acer-Aspire-E5-571G-59CT/td-p/344235
Make sure you get the correct keyboard (US or UK layout) for the exact correct machine.
XXX
July 2016