If Yahoo! Messenger is crashing when you try to broascast your webcam, try the following fix:

1. Shut down Yahoo! Messenger if it is currently running.
2. From the Windows "Start" menu at the left bottom of your screen, click "Run."
3. From the input area, type regedit and press "Enter." The registry editor application should open.
4. On the left side, expand the "HKEY_CURRENT_USER" folder (or key), then expand the "Software" folder under it and select "Yahoo."
5. If there is a "Webcam" folder, go to the next step. If there is no "Webcam" under the "Yahoo" folder, go to the "Edit" menu and click "New Key" and type "Webcam."
6. Select the "Webcam" folder.
7. From the "Edit" menu click on "New" then "DWORD Value" and type "UseVFW" without any spaces.
8. Double-click on the entry "UseVFW" and change the entry in Value data to "1." Then click "OK."
9. Exit the Registry Editor application.
10. Restart Yahoo! Messenger and try starting your webcam by clicking "Start My Webcam" from the "Messenger" menu located in the Yahoo! Messenger window.

Note: If you are on Windows 2000 or XP, you must be logged in as an administrator for these registry entries to be updated successfully.