It's driver dependant. Intel 950's don't have hardware vertex support, but some drivers provide software emulation.

Last I checked there was 1 driver for Vista that claimed to have working shader emulation, but even then it's not guaranteed. You can thank OEM manufacturers for that.

*EDIT*

Seems people are still confused about the whole shader hardware thing. I'll re-write & update the FAQ to clear things up when I've got 5 mins.