How do I turn off a selector?

How do I turn off a selector?

Good day,
 
I have a global stylesheet.  In that stylesheet I have:
  1. .index .left #search_accordion .flyout {position: absolute; top: -9px;}
        I need to turn off the top:-9px, because IE7 renders my menu wrong with it there.
        I have a stylesheet for IE that overrides global which I set to:
            1. .index .left #search_accordion .flyout {position: absolute; top: 0px;}
            2. or
            3. .index .left #search_accordion .flyout {position: absolute;}
              4. .
              When I make top:0px, I get the wrong positioning.  When I leave don't include the selector "top"  then the browser pulls the value from the global stylesheet (top:-9px). The solution is I need take "top" out completely.
                Does anyone have any ideas on how to do this?