I just finished creating my very first short video....love the program. I rendered the file as an mpeg then burned a copy onto a cd. I did a test run on my home system to make sure the video played and it worked fine. I brought the disc into work and it won't play. I get a message that says "invalid media type." When I click on "details" this message pops up "The appropriate codec is not installed on your computer". I can see wmp attempting to download the correct codec but it can't seem to find the one needed. I have wmp 7 and I checked the security settings (which is what wmp suggested) but still no luck. Any help is much appreciated.