Keyboard thing

I’ve had an issue over the past few weeks of odd keyboard buffering — most often manifesting with “Hey, I let go of the [w] key but I’m still running forward toward that very unfriendly group of purple mobs!” Well, I thought I was actually wearing out my keyboard, but now I’m thinking that’s not the case.
Last night, the same thing happened a couple of times dodging to the side (and running uncontrollably against the wall for a few moments).
And I’ve realized I’ve had a coincident problem with typing, where suddenly my typing in the chat window will queue up for multiple moments, with nothing coming out for a second or two, then the keyboard buffer slowly emptying. Which is, I’m thinking, the same problem (e.g., the [w] gets queued up while pressed and continues to then execute even after I let off the key).
Question is — WTF? And how to do I fix it?
Need to go to the boards, when I get a chance …