Please Help!!

public void act()
    {
       boolean guess = false;
       
       if(!guess){          
           if(isDown == false && Greenfoot.isKeyDown("space"))
           {
               currSong = Random();
               Greenfoot.playSound(songs[currSong] + ".mp3");
               isDown = true;
            }
       }
       
       if(guess){
           if(isDown == true && Greenfoot.isKeyDown("space")== false)
           {
               isDown = false;
           }
       }
       
       if(String.valueOf((currSong + 1)).equals(Greenfoot.getKey()) )
       {
           if(!guess){
               isDown = true;
               scr.addScore(5);
               guess = true;
            }           
           else if(guess != true){
               Greenfoot.setWorld(new Gameover());
            } 
        }
            
       if(guess){
           if(isDown == false && Greenfoot.isKeyDown("space")== true)
           {
               Greenfoot.playSound(songs[currSong] + "mp3");
               isDown = true;
               guess = true;
           }
           if(guess = true)
           {
               isDown = false;
           }