hard-reset

To perform a forceful restart or reinitialization of a device, system, or process, typically by cutting power, or using a dedicated button.

Do not hard reset the computer while you're using a disk caching program!

I have a Sony Clie S-360 with a broken power button (I managed to drop it, of course :-) So far, I didn't miss any functionality because I used a hack to remap the To Do button into a power button, but now I need to hard reset the unit and I'm not quite sure how to do it.

To factory reset a device.

As soon as I pulled back onto the road I realized my one grave mistake: hard resetting the Zumo had erased everything that was stored in the system; gone was my tiny blue track that had followed me for months; gone were my trip statistics - all gone.