I have just bought a Pioneer VSX421V-K 5.1. The only Connections i have on my Computer is 3.5 mm jacks on board (msi z68a-g43 (g3)) sound and i have a xfx radeon hd 7770 graphics card. i cannot seem to get my graphics card to send 5.1 sound over hdmi to the receiver and the on board jacks will not connect to my av receiver. if there is no way for me to get true 5.1 sound from my pc, what sound card (looking around £50) with optical audio should i buy which would give me good 5.1 sound?
I mainly use my PC for movies and games and sometimes music.
First thing I would suggest is making sure you're using the latest drivers from AMD for your card, they include an HDMI driver.
Then I would go into Sound in the Control Panel to see what the output device is for your Sound Card. It could just be that your system is currently set to direct sound out through 'Speakers' which would mean it would go through your on-board sound.