Missing Icon Image

Hi, sorry to bother you so soon after my last problem.

Earlier today, I broke my Mozilla Thunderbird desktop shortcut icon. The quicklaunch icon and taskbar icons appear as the Windows default icon (dogeared sheet of paper). I tried unpinning it from the taskbar and deleting the desktop and quicklaunch icons and creating a new desktop shortcut, but the problem persisted. When I right-click the shortcut and select Properties, the Shortcut tab showed the Windows default icon. When I clicked Change Icon and selected the correct icon, the tab showed the correct icon, but the problem persisted, and the next time I opened the properties dialog, the Windows default icon was back. I uninstalled Thunderbird, downloaded it and reinstalled it, but the only difference is that now, I managed to get the Properties dialog to show the correct icon permanently, and the quicklaunch icon is also correct. It still shows the Windows default icon on the taskbar when I launch Thunderbird. Is there a way to fix this?

(I'm not in any hurry to get an answer, since this is really more of a nuisance than anything else. If I knew a way to assign a priority to posts, I'd give this a low one.)