Log in to Windows Live Messenger.
Click the "Show Menu" icon in the upper right corner of the window.
Click "Tools," then click "Audio and video setup."
Click the drop-down menu at the top of the window,
and choose "Disable." Click "Finish."
Sign out of Windows Live Messenger and sign back in.
Your webcam will be hidden from your contacts,
reducing the likelihood of further requests for you to video-chat.
Tips & Warnings
* Note that disabling your webcam in Windows Live Messenger or MSN Messenger will prevent you from being able to use it at all.
Repeat the steps described in this article to turn your webcam back on if you would like to have a video chat.