Right click the icon and open the Properties. Click the icon and browse to the location of the Firefox program directory to update the icon.

Well, the problem was finding that icon file, your post helped me to believe it was there, someplace, I did find it, and everything looks as it should. Thanks.

You're welcome.

If a shortcut is still working then you should find the location of the program in the Properties of that shortcut or you can go to the Desktop directory in your Home directory and inspect the .desktop file with a Viewer or Editor.

Sorry maybe I am not smart enough. Can you explain in more detail how to find the icon file?

I assume that you are on Linux as well?

Did you right-click that desktop icon and open the Properties?

There you should see the location of the program file in the command field.
You can click the icon and browse to that folder and then open the icons folder.

No I am using Windows XP

When I find the location of where Firefox is installed, the icon on the exe is missing as well. Firefox will start OK, but it's an annoyance.

icons, toolbar , everything disappeared.

This worked on my MacBook: Go to Applications and move Firefox to the trash. Open the trash and move Firefox back to Applications.