How to get rid of navigation bars in beamer

The section navigation at the top of the frame is part of the headline. The easiest way to remove it is to change the headline template.

The line \setbeamertemplate{navigation symbols}{} is unrelated to the sections in the headline, this will remove the little symbols at the bottom right if the frame.

\documentclass{beamer}

\setbeamertemplate{navigation symbols}{}
\useoutertheme{shadow}

\setbeamertemplate{headline}{}

\begin{document}

\section{title}
\begin{frame}
\end{frame}

\end{document}

I don't know whether this is what you want, but if you are talking about the navigation bar which has the symbols you can click on, this is the way to go:

\beamertemplatenavigationsymbolsempty

Funny, that is the second time you ask this....

By the way, you might want to check this proposal for a question/answer website focusing on LaTeX.