Sound card problem

I hope I explain this right. I installed a new sound card into a computer that is used to run a program called Media Play. It is used for a school channel that broadcasts school ads over cable and also plays the weekly football game the following week. Anyway after installing the new card the music that plays for the ads work fine. When the game starts to play the software acts crazy and turns down all the knobs to off. The line in where all the sound is coming from does not work until I go in and turn the line in back up. No matter what I do every time the scheduled game starts it turns it down so no sound comes on. Does anyone have any idea what could be happening? Thanks. I will try to contact the company that sold us the computer but they are not easy to get a hold of.