documentclass[margin, letterpaper]{res}
...
...
% LaTeX resume using res.cls
documentclass[margin]{res}
%usepackage{helvetica} % uses helvetica postscript font (download helvetica.sty)
%usepackage{newcent}   % uses new century schoolbook postscript font

setlength{textwidth}{5.2in} % set width of text portion
usepackage{enumitem}
addtolength{textwidth}{.5in}
addtolength{textheight}{2in}
addtolength{leftmargin}{-.1in}
begin{document}

% Center the name over the entire width of resume:
 moveleft.5hoffsetcenterline{largebf Stephen Leone}

% address begins here
% Again, the address lines must be centered over entire width of resume:
raggedright hspace*{-sectionwidth}{287 Warren Avenue}hfill sml94@live.com\
raggedright hspace*{-sectionwidth} {Hawthorne, NY 10532}hfill (914) 980-4235\
vspace{4mm}
% Draw a horizontal line the whole width of resume:
movelefthoffsetvbox{hrule width 505 pt height 1pt}smallskip

begin{resume}


section{EDUCATION} {sl Bachelor of Engineering} in Electrical Engineering, Expected Spring 2016\

documentclass{article}
usepackage[letterpaper,top=3cm,bottom=3cm,left=2cm,right=2cm]{geometry}

usepackage{helvet} % uses helvetica postscript font (download helvetica.sty)
renewcommand{familydefault}{sfdefault}

usepackage[parfill]{parskip}

usepackage{titling}
author{Stephen Leone}
title{Resume}

begin{document}
    pagestyle{empty}
    begin{center} largetextbf{theauthor} end{center}

    begin{minipage}{0.2textwidth}287 Warren Avenue\sml94@live.comend{minipage}%
    hspace{0.6textwidth}
    begin{minipage}{0.2textwidth}Hawthorne, NY 10532\(914) 980-4235end{minipage}%
    smallskip
    hrule

section*{EDUCATION} textit{Bachelor of Engineering} in Electrical Engineering, Expected Spring 2016

end{document}

documentclass[margin]{res}

begin{document}

% Establish mywidth as width of entire resume (since res.cls co-opts textwidth!):
newlengthmywidth
setlengthmywidthtextwidth
addtolengthmywidth{sectionwidth}

% Center the name over the entire width of resume:
moveleft0.5hoffsetcenterline{Large Stephen Leone}

% Contact info centered over entire width of resume:
raggedright hspace*{-sectionwidth}{287 Warren Avenue}hfill sml94@live.com\
raggedright hspace*{-sectionwidth}{Hawthorne, NY 10532}hfill (914) 980-4235

% Draw a horizontal line the whole width of resume:
movelefthoffsetvbox{hrule width mywidth}

% Begin the resume environment:
begin{resume}
section{EDUCATION} {sl Bachelor of Engineering} in Electrical Engineering, Expected Spring 2016.
section{HOBBIES} {sl Engineering} I do engineering in my free time as well!
section{LOVES, LUSTS, & ALLEGIANCES}  Just engineering.  Engineering, engineering, engineering.

end{resume}
end{document}