Weird Screen blanking - codec overlay issue with videos in mamewah

[stuzza]

I'm setting up another mame pc at the moment and have struck a weird issue which I think is caused by the video codec/graphics overlay setting.  I have been running Mamewah for years with no problems.  I recently built up an old pc (intel DG35EC motherboard) and copied my entire mamewah folder and emulation folder over as I normally do.  I have all drivers for the mainboard, onboard graphics etc.. installed.  I ran the system files batch file installer for mamewah.  I installed the K-Lite codec pack.  machine is running windows xp pro sp3.

When I launch mamewah the screen goes black for about a second everytime I change a game and the video for that game plays.  I have isolated it to the codec as the same thing happens in windows media player when I play any of the preview videos.  if I turn off "use overlays" in the windows media player options it fixes it in media player but not in mamewah.  If I uninstall the codec mamewah works fine, however ofcourse the video previews don't play?

Any ideas??