How to tell hyperref to link to a file on my disk?

[MK]

Dear friends,

In a file whose preamble contains:

%! program = pdflatex
\documentclass[]{article}
\usepackage{termcal}
\usepackage{color}
\usepackage[colorlinks,
citecolor=blue,linkcolor=blue,pagebackref,pdftitle={PSYC712-1---Cognitive
Methods}]{hyperref}
\usepackage[authoryear]{natbib}
\usepackage{checkend}
\usepackage{amsfonts}

...

The link

\href{http://www.google.com}{google}

works, but neither

\href{file:///Users/mk/Desktop/introex2.pdf}{Conceptual}

nor

\href{file:///localhost/Users/mk/Desktop/introex2.pdf}{Conceptual}

work.

What am I doing wrong?
_____________________________
Professor Michael Kubovy
University of Virginia
Department of Psychology
USPS: P.O.Box 400400 Charlottesville, VA 22904-4400
Parcels: Room 102 Gilmer Hall
McCormick Road Charlottesville, VA 22903
Office: B011 +1-434-982-4729
Lab: B019 +1-434-982-4751
Fax: +1-434-982-4766
WWW: http://www.people.virginia.edu/~mk9y/