Had this happen to me last night. Was playing a game, and my camera controls are all default, so W moves forward, and S moves backward. I pressed '0' on the number pad, followed by "Num Lock" and it changed my W key to zoom, and S key to zoom out. I did the combination again and it reverted back to forward/backward.
I was using 1.7.2. Anyone know anything about this?
Changing controls mid-game?
Re: Changing controls mid-game?
Sounds like your keyboard is malfunctioning.