Characters turning into odd symbols and fonts on laptop.

I've had my laptop for almost a week, and I could never figure out this
problem while typing: sometimes when I type, and my finger moves near the
shift key and presses (dunno what key specifically, I don't look at the
keyboard.), my font changes to a selection of weird things, and I can never
seem to get it back, unless I restart the comp, save for today, when I went
through an array of different key combinations, and eventually it started
typing normally. But I don't know what I pressed, and can't find it anymore.
Help would be appreciated. This is some of what I've seen:

ÉÈÃ* /, as well as some strange chinese characters, and an insanely huge font.