\documentclass[pdftex, a4paper, german]{scrlttr2}

\KOMAoptions{%
 fromalign=right,%
 fromrule=afteraddress,%
 fromphone=false,%
 fromemail=false,%
 fromurl=false,%
 foldmarks=off,%
 backaddress=false,%
 addrfield=false,%
 %footsepline=true,
 %headsepline=true,
 enlargefirstpage=true
}

\usepackage[ngerman]{babel}
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}

% Sans Serif Schrift
\renewcommand{\familydefault}{\sfdefault}
\usepackage{helvet}

% Kopfzeilen
\firsthead {
  \begin{flushright}
    \textsc{\usekomavar{fromname}}\\
    \usekomavar{fromaddress}
  \end{flushright}
  \hrule
}

\setkomavar{fromname}{Michael Puff}
\setkomavar{fromaddress}{Schulstraße 1\\34246 Vellmar\\Deutschland}

\begin{document}

\begin{letter}

\setkomavar{place}{}
\setkomavar{date}{}
\opening{}

\end{letter}

\end{document}