Okay, I always install the codec individually.
The problem is that the codec associates itself to a specific PROGRAM. There are more 'smart' players out there that do see that the codec is installed and use it, but some other players (Windows Media Player for instance) just doesn't like it when it tried to access my AC3 codec cause according to GSpot it was associated to my Nero program.
Simple solution would be: Dont use Windows Media Player, but I'd like to know why this is a problem. And like I've said I'm not the only person that has this problem. I would like to know why certain codecs attach themselves to specific programs...
Anyone anymore ideas? (sorry for the late reply but I thought nobody was able to help me seeing that there wasn't much activity on my thread :))