I too had the problem with the main window disappearing, and tried EVERYTHING. I came here looking for an answer to this problem. I didn't have any idea what the problem was, but when some of you said that the window disappeared while you were dragging, etc., I had an idea, and it worked! When you open Limewire and see the little sliver of a window on your screen, click and hold down the mouse -- you should see the lower right corner of the window and should be able to click on the lower right corner and drag to the right to expand and open the window (I did this with my right mouse button, but I think it would have worked with the normal mouse button) and now it works perfectly!!!