I guess I know what is your problem. You have probably opened one of the aero cursors from Windows 7 or have created a Windows 7 cursor. These actually have 2 images in them, one used for normal resolution, another one used for high resolution displays. You should modify both of them. If you only modify for example the larger one and you are using standard resolution mode in your Windows, you will not see the change. If there are multiple images in your cursor, you can switch between them in the upper left part of the windows. When I am talking about a window, I mean the window of the editor. It has only one.