how can I get LibreOffice to load when windows starts up?
Under Tools, Options, +LibreOffice (expand it), Memory, LibreOffice Quickstart section at bottom, CHECK Load LibreOffice during system startup.
See also:
(1) This answer (from TonyKl)
(2) Quickstarter minimised to taskbar becomes template manager
There is a checkbox when installer runs that reads as if it would load LibreOffice during system start-up, but checking it never did anything for me; I always had to use Tools | Options and go to the above settings to set the option.