Yes.. there it is, just like I warned against in my first post..
 setBounds(0,0,200,100);

Try this code on both machines, I am guessing it
will look slightly different on each PCs, but should
work well for either.

<sscce>
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

import javax.swing.border.EmptyBorder;

public class DoesStuff extends JFrame{

 public DoesStuff() {
   super("Frame");

   JPanel layout = new JPanel( new FlowLayout() );

   // I will want to use a Border, so will
   // .. use the panel above..
   // setLayout(new FlowLayout());
   setContentPane( layout );

   //setBounds(0,0,200,100);
   layout.add(new JButton("Button1"));
   String[] stuff = {"Option1","Option2","Option3"};
   layout.add(new JComboBox(stuff));

   // add spacing around the panel..
   layout.setBorder( new EmptyBorder(10,50,10,50) );

   setDefaultCloseOperation(EXIT_ON_CLOSE);

   // packing a layout will both validate
   // it, and change the root component to the
   // size it *needs* *to* *be*.
   pack();

   // if you insist* on calling setBounds/setSize,
   // do it after the call to pack or validate.

   // setSize( 200,100 );

   // though note that such 'spacing' can best
   // be achieved by adding an EmptyBorder, like above

   setLocationRelativeTo(null);

   setVisible(true);
 }

 public static void main(String[] args) {
   Thread t = new Thread() {
     public void run() {
       new DoesStuff();
     }
   };
   SwingUtilities.invokeLater( t );
 }
}
</sscce>

...

There are lots of extremely poor layouts, mostly those
designed in IDE's by people that think they can drag
components anywhere they like and assume that will
'just work' for anyone else's VM version, screen
size/resolution, default font face & size, PLAF..

Try the altered code.  Note that I do not actually set
the size of any component in that code, as it is.