Knight Rider on DVD.com.
I checked just now. If, for whatever reason, you don't have / aren't able to stream KR on Netflix, but have an account at DVD.com, (which is a Netflix company), you can rent the DVD's.
All 4 seasons are available, and you can find the movie Knight Rider 2000 in the first season. (It says 6 DVD's per season, so I'm assuming these aren't the single-sided releases.)
As a side note, through December 1 to December 22, for every title you add to your DVD queue, Netflix will donate one meal to Feeding America.