I think your problem may lie here:
glOrtho(0,Display.getWidth(),Display.getHeight(),0,1,-1);
In OpenGL, coordinates go from -1 on the left of the viewport to 1 on the right, and -1 on the bottom to 1 on the top, with (0,0) in the center of the screen (and the Z axis going back to front). This is the same regardless of the shape of your viewport, and it is completely up to you to make some sense of these coordinates.
So usually you want to change this coordinate system to something that makes more sense. That is what the projection matrix is usually used for. One way to change your coordinate system is to use an orthographic projection matrix. glOrtho() offers a way to create one.
The first two parameters define where the left and right borders should go to. In your case, left is set to 0, and right is set to the display width (make sure this is what you want. If you're in a windowed application, you want to set this to the client area of your window, not the entire display width).
The next two parameters define where the bottom and top borders should go to. In your case, bottom is set to the display height, and top is set to 0. This effectively makes your origin to be set at the top left of the screen. If you want your origin to be set at the bottom left, you can invert these two parameters.
The final two parameters define where the near and far borders should go to. This is the same as before, but with the Z-axis.
Here's a nice tutorial that explains the coordinate systems in OpenGL.