One of the tricky things about this is that media may play perfectly fine in WMP (any version) and yet not look or act the same in MediaLab or DirectRT even though our programs use the same technology. We're just coming to understand this stuff now. It seems there are licensing issues whereby certain codecs used by the WMP (for example) will only function in Microsoft applications. This is one reason some users might get video but no sound. Installing the ffdshow is a workaround for this. I have yet to see that it doesn't help when WMP 12 is installed but that might be true--may I ask where you read that? Most cases we are looking at are usually Windows 7 machines though so it'd be odd. Is it something you could at least try? Can't speak to the "home" version--haven't played with it much.