In Internet Explorer the yoom button (shows a percentage) is usually in the bottom right corner of the screen. If just clicked it goes 100-125-150-100. If the "pull up" is activated, other choices are available.
That happens occasionally when you use an English/US keyboard at home and a german keyboard at work (for the alphabet only the Y and Z keys are swapped).
Plants vs. Zombies and Hammer Heads are both from PopCap and therefore the digital equivalent of crack.