How to create a list of file fields with checkboxes selector?
Add 4 file fields to your content type with desired labels (ex. "Win 64bit"),
Then you will have this 4 fields in your add content form.

Now it's time to make them optional, first of all using hook_form_alter you can add 4 new elements of class "checkbox" to your form like this:

$form['dependent']['win64'] = array(
  '#type' =&gt; 'checkbox',
  '#title' =&gt; t('Win 64bit'),
);


and then for your fields add a #states like below : 

$form["win 64 file field"]= array(
  '#states' =&gt; array(
    'visible' =&gt; array(
      ':input[name="dependent[win64]"]' =&gt; array('checked' =&gt; TRUE),   
  ),
);