My camera stopped working after upgrading to 5.5.
Please refer to the Webcam Issues section in the main help page to see if it addresses your specific problem. There was an issue in Messenger builds below 1232. In most cases, installing the latest build should fix your problem.
If you still cannot see your image in the My Webcam window, then try the following.
Shut down Yahoo! Messenger if it is currently running.
From the Windows Start menu in the bottom left-corner of your screen, click Run.
In the input area, type regedit and press Enter. The registry editor application should open.
On the left side, expand the HKEY_CURRENT_USER folder (or key), then expand the Software folder under it and select Yahoo.
If there is a Webcam folder, go to the next step. If there is no Webcam below the Yahoo folder, go to the Edit menu and click New, Key, and type Webcam.
Select the Webcam folder.
From the Edit menu click on New, DWORD Value, and type UseVFW without any spaces.
Double-click on the entry UseVFW and change the entry in Value data to 1. Then click okay.
Exit the Registry Editor application.
Restart Messenger and try starting your webcam by clicking Start My Webcam from the main window’s Tools menu.
Note:If you are on Windows 2000 or XP, you will need to be logged in as an administrator for these registry entries to be updated successfully.