Video-chat problem - need some advice or suggestions.

Windows XP Pro SP3 32bit.
Windows Live Messenger 2009 Build 14.0.8089.726
Microsoft LifeCam VX-6000 webcam.

In Messenger video-calls, I can see and hear the other person, but I cannot see myself on the webcam during the video-call. The lower part of the Messenger-video-chat window (where I normally see myself) shows a red-coloured X over the webcam icon. The other person hears and sees me correctly during the video-call.

Using the Messenger Tools -> Audio and Video Setup -> the microphone and webcam settings are OK and I can see myself in the webcam window under 'Set Up Audio and Video - Webcam' window.

I uninstalled and re-installed Windows Live Messenger, made no difference to symptom.
Using Start->Microsoft LifeCam -> Dashboard -> Check For Updates : reports that no newer version is available. The video works correctly in the Microsoft LifeCam window, can see myself OK.

If I move the webcam to a different machine, the Windows Live Messenger video-chat feature works correctly (same versions of VX-6000 driver, Windows Live Messenger).

It used to work correctly, originally with a different webcam. Possibly related to installation of a new version of the VX-6000 driver (not sure of this).

Have you enabled the webcam in the little control panel to the left of your webcam viewscreen?

krissy-afc asked if the webcam was enabled. Of course it must be because the other party in the video-chat and see/hear me, and I can see/hear them. Just that the bottom half of the screen (which normally shows myself) instead shows a red X.