When I run my game the main menu disappears after 10 seconds

I have built my game, but when I run it, the main menu disappears, and it loads up the first scene in the game, after about ten seconds, even when you haven’t clicked ‘Play Game’. I am using this code to do it:

function OnMouseEnter() { //load level named 'level 1'
  Application.LoadLevel("1"); 
}

how can I stop this from happening? Any help will be greatly appreciated

Don’t use MouseEnter, if you move the cursor into a collider it will be triggered, unless that is what you wanted instead of OnMouseDown(click)