Hello i just answer the question, i did not check the computer model, and what is possible! It just indicates that the computer, in its current configuration, can only run with one device, 5.1 .. Although sometimes it is mentioned that it does not work directly, that the computer can not finally have 5.1 without adding something So, if you want 7.1 you will have to buy a compatible audio card that allows it!
I looked at the detailed specifications for your computer and motherboard. It looks like you should have a free x1 pci-express slot! If so the 7.1 sound card called "Creative Technology SB1550 Sound Blaster Audigy RX 7.1 Sound Card" would fit in your computer!
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