Re: Sticking Windows where it's not easy to get at.
Actually, if you lock down both the hardware and software configuration (as you would in an embedded system) Windows is perfectly stable.
I've seen it used in both safety critical applications (air traffic control, military radar control, in an x-ray imaging system system for use in key-hole surgery) and in remote infrastructure (as supervisors in wireless base stations). In the latter configurations the average 'tech' might not know anything about the O.S. They just get told by email that a board in location X has failed, they drive out, pull out the module with the red light, put in a replacement and wait for the light to go green.
It's only when you throw in a bunch of cheap RAM from PC-world, some dodgy drivers for some no-name hardware and allow the user to install crapware from web that Windows turns to shit.
That said, this kind of stuff is all very much at the top end of embedded systems in terms of performance. In terms of volume it is dwarfed by the number of ARM and myriad lesser embedded systems out there. As has been said elsewhere, any high end system will probably have a few low end micro-controllers running independent sub-systems.