rails server command not starting server -

i new rails , trying run application on windows 8. whenever try start server using "rails server", gives me this:

usage:   rails new app_path [options] options:   -r, [--ruby=path]     # path ruby binary of choice 

etc, think picture. have gotten server running several times before, , assure in application directory. please provide explanation why happen? if need more information, feel free ask.

checked value of path (echo %path%) if ruby not in there add manually:

set path=c:\ruby200-x64\bin;%path%

i've installed rubyinstaller windows (the "ruby 2.0.0-p247 (x64)" version) config path version.