The hitTest
Let's make things more interesting. Draw a small circle and convert it to a movie clip. Call it "button_mc". In it's Actions, put this:
onClipEvent (enterFrame) { if (this.hitTest(_root.player_mc)) { _root.lock = "open"; this._alpha = 50; } }
This basically tells the MC that when the MC is in the frame, check if out player ("player_mc") is touching the button. If it is, then it sets the variable "lock" to "open" and sets the button's alpha (transparency) to 50%. I used the variable "lock" because it's useful. I'll tell you how. Create a sign or rectangle, then place a dynamic text box in it. Set the text box's variable by typing in "lock" without the quotes into the 'var' box in Properties. Then, in the empty text box, type in "locked". Now test your movie. You should have something that does this:
I hope that went well for you and I hope that you can go on to make a better example than this.