Medialab playing movie files in hidden window

I'm trying to get Medialab to play some short .wmv and .avi files (tv ads). I converted .flv files from adforum to .wmv and .avi files using RealplayerSP.

I've inserted them as movie items in questionnaires. But when I try to run the questionnaire, a black rectangle appears and the video doesn't present (but I could hear the audio). It’s like Medialab is playing the movie file but in a hidden window.

I've checked and the videos do play in Windows Media Player with no problem. Also, I’ve restarted my computer several times. I'm running Medialab 2006.2.4

Any idea what the problem is and how to fix it?

Thank you so much!
XianXian

I tried everything in this thread: [URL]http://www.empirisoft.com/support/showthread.php?t=552[/URL]

And nothing works for me.

Even when I closed Medialab, I still hear the audio. It seems that it's playing somewhere hidden. It's driving me nuts..

Please help!

Xianxian