So I have a DFI LANPARTY DK X48-T2RS motherboard with RealTek ALC 885 onboard sound playing. I have a logitech 7.1 surround sound system going and it sounds not too bad with music and games but I plan on getting a sound card sometime. The only problem is when I have my speakers set up, it will play games and music fine, but when I play videos on the internet like on youtube or something NO SOUND WILL PLAY. I'm really stumped and I've tried changing it from 2 speakers to headphones to 7 speakers and everything, with no luck. I even tried reinstalling the driver for it. I can hear the youtube videos when I plug my headphones into my front jack of my computer, but that's it. I'm stumped.
Have you tried in realtek to "set deafault device" to speakers rather than digital output..? I had the same problem until I tried that.. and now.. works perfect! hope that helps. =]