I had the EXACT same issue as described here and I just wanted to add what worked for me. The screws on the bottom of these laptops can quite easily fall out and I had noticed that 2x screws were missing from the bottom of my laptop.
I then noticed that applying pressure where the missing screw was enabled me to make the top row of keys work again.
Simple fix - either tighten or replace the screws in the base of the machine.