I'm not sure if it has been posted previously, but this article provides not only a comprehensive outline of Objectivism, but also describes its fundamental differences from conservativism in philosophical language. Here is a brief excerpt:

It is widely believed today that our moral, cultural, and political alternatives are limited either to the ideas of the secular, relativistic left—or to those of the religious, absolutist right—or to some compromised mixture of the two. In other words, one’s ideas are supposedly either extremely “liberal” or extremely “conservative” or somewhere in between. Ayn Rand’s philosophy, Objectivism, rejects this false alternative and offers an entirely different view of the world.

Objectivism is fully secular and absolutist; it is neither liberal nor conservative nor anywhere in between. It recognizes and upholds the secular (this-worldly) source and nature of moral principles and the secular moral foundations of a fully free, fully civilized society.