Uninstalling the voice and video chat plug-in
To uninstall in Windows:
Click Start > Settings > Control Panel.
Double-click Add or Remove Programs.
Scroll down to find Google Talk plugin.
Click Remove, then Yes, then Finish.
To uninstall in Mac OS X:
In Finder, navigate to Applications > Utilities
Open the Terminal application.
Copy and paste the following command into the window: /Library/”Application Support”/Google/GoogleVoiceAndVideoUninstaller.app/Contents/MacOS/GoogleVoiceAndVideoUninstaller
Press Enter on your keyboard.