No sound on e-cards.

I have a system on which I reformatted and reinstalled NT 4 workstation. I used the drivers for the sound card that came with the pc and all the sound devices show they are working properly. We can listen to a music cd fine and can hear all the windows sounds but we cannot get any sound on those e-cards sites and we have a cd with some fancy little advertisement on that has no sound. It works fine on an identical computer except for the fact that it's os was factory installed. I am thinkingit is something I didn't install like a plugin or something. I thought installing java VM would work but it didn't. Any suggestions?