More on Post Filtering

I am attempting to show only one category on the main page but isolate any other categories to show only when that page is directly visited through a link, i.e. “News and Updates” should show on the front page but if you click a link to an additional category it should then show that category’s posts on that page.
I have read this entry, which seems to be the most relative (but not exactly) to what I am looking for but I am still having problems:
http://wordpress.org/support/10/1385
This is what my index page looks like now:
$cat = “2”; //Change number to show one particular category according to ID.
//if ($cat == ”)
//$cat = -14;
(Remarks are on purpose for personal reference.)
The problem is that although the category is filtered from the front page, when I click on a category link the category’s post doesn’t show there either, obviously due to the filtering.
What code should I add to this to allow category content to show on their own significant pages without posting to the front page?
In the above thread, one of the authors stated that this has been mentioned many times before but I have searched repetitively to no avail.