java applet button problem .. :( plz help

[i4gotmyid]

my game applet starts with 2 push buttons START GAME and
VIEW SCORES

1.a thread starts when "START GAME" button is pressed.

>>

if(str.equals("START"))
{
t1=new Thread(this);
t1.start();
}

but the problm is that the "START GAME" button still appears in the screen while the game is running ..
how can i make it such a way tht the button dissapears after it is cliked ?

2. How is it possible to run 2 differnt threads(havin differen RUN body) in a program ?
I need a different thread for the View Score section ..
But once the run function for 1st thread is made , wer wil the other thread's run function be written ?

3. How can the Buttons be placed in a coordinate x,y ?
i tried using button.setLocation(int x,int y) but it seems to be not working
and how can i increase size of button

my class extends Applet class, implements Runnable and ActionListener

help!!