  :Well, its still there, albeit it may not be quite as visible as it once was.  Boot sector viruses became less of an issue post Windows 95 so perhaps boot sectors have dropped off the radar as far as the average user is concerned but they are still of vital importance.  Most of it hasn't even altered that much - it needs to remain the same for the sake of IBM compatibility. The only real change has been evolution in supported boot media - first CD-ROMs and now USB drives, although those are more BIOS changes that changes to the actual boot sectors themselves.   