Q: Playing .avi files in Front Row has stopped

Hi,

I've had my iMac for about 3.5yrs and Front Row has always read .mp4, .m4v and .avi files with no problems (providing i navigate to /Movies/Movies Folder, not /TV Shows because that only reads .mp4 files the same as iTunes & Apple TV), up until a couple of days ago. When i navigate to an .avi file now it plays the file, has the correct time length indicated but all have no sound and black screens.

Is anyone aware of any updates that could've stopped this? how it was casued or know how to get around it?

Thanks.

TG