Yes, I fear the two previous posters are right. We had the same problem, called in the double glazing experts and this was the only solution. shop around and get a couple of quotes - in these difficult times there could be a wide disparity between prices. You could check whether your insurance company would cover it but I suspect they will claim it is normal wear and tear unless the windows are still under warranty, in which case the original installer should come and replace the panes.