Q:

How to disable layered navigation on certain categories

I want to disable the layered navigation on some certain categories, can someone help me?
case 1: 

disable it through category id, for example on category id 4

case 2: 

only disable it on parent categories. For example, if category A has
  subcategories, disable it on category A. But it will be shown at
  category A's subcategories

A:

Hi if you want to delete you layered navigatino category wis then you can use below:
Admin Menu:
catalog->cateogry

1.Select your category.
2.open custom design tab.
3.add following code in Custom Layout Update:
<remove name="catalog.leftnav"/>

4.Save cateogry.

