Help on movie clip set properties

Okay, heres the deal. I have a good guy and a bad guy. Its stop time control, so, the bad guy only acts when the good guy does. the thing is, the good guy can only move horizontially or vertically while the bad guy can only move diagonally torwards the good guy, where theres is a collision and then game over. My questions are as follows;

  1. How can I make it so that the bad guy will always go towards the good guy
  2. Can I set up a collision detection that sends an effect only when the bad guy sprite is 100% covering the good guy sprite, and how.

Please help. I beg of you.