The codecs that came with your computer (pre-installed) are probably not the problem...I installed the codec packs that were causing me trouble. To uninstall them, all I did was go to add/remove programs, and the codec pack was listed there. The other codecs that I have installed individually also show up in my program list under add/remove programs.

You probably don't even want to know how many codecs are on your computer that you will never use...I just took a look at mine and the list is quite long, even after uninstalling the codec packs.

With AVICodec you can see exactly what codecs are installed on your computer. It even breaks them up into video, audio, directshow, etc.

Plus, if you drag and drop a file into AVICodec, it not only tells you if you have the necessary codecs installed, but also has links to where you can get the codecs if you don't have them.

Hope this helps

Dano