Incorrect display drawing graphic in PictureBox in customer pc

Question

I used system.drawing.graphic in C# to draw the Rectangle and Ellipse in PictureBox. That PictureBox is 512x512 ratio. In my PC and other my buddy PC show the drawed graphic .

But in my customer PC, the drawing graphic not work well function and system draws many rectangles in the whole PictureBox, cannot set position.

In my customer PC, already installed .net Frame Work 2.0 (SP1) and OS is Window XP. I don't know what is missing? I write some codes in below from my project...


Pen penMi = Pens.Blue;
void DrawAllMi(Graphics g)
{
g.DrawRectangle(penMi, x1 - 4, y1 - 4, 8, 8);
g.DrawEllipse(penMi, x1 - 5, y1 - 5, 10, 10);
}

Please give me some suggestion,
Thanks.