Ok, it might be as you say - the case and keyboard might be "squeaky" so ... open up the machine (if you want) and you will see that the keyboard is not actually "fixed" in place, it just sits in little plastic brackets at the narrow side of the wedge. Given that that is the situation, try pushing/forcing (gently now) the keyboard about a bit without opening the case up first. It might create the clearance that you need to allow the Esc key to operate freely.
