Windows 7-64 Does Not Support 5.1 Speaker?

I boght a soeaker 5.1 channel and I found later after 3 weeks of trying to connect it with my win 7-64 is there was no SPDIF port.However, I will post pic for my pc and my TV and the speaker so you can tell me how I connect them and if I need to buy adapterThis is my TV it is Sceptre 32 LEDI am using HDMI Now this is my Speaker from Acoustic AA 5102This came with bad manual, it is only says were it is says DVD audio input, I should connect it to my DVD. I do not have DVD, and also for the two top AUX input its says that for PC. This is my PC, I am using gig 990fxa-ud5 and it is supporting 5.1

For now I want to say some thing, when I use this caple ( I have 3 oh this and i connect it ith my pc were Green and Orange and Black) from my speaker to my PC( in the speaker were its says AUX audio input L and R)I can go and set up my speaker to 5.1 so I can hear all the speaker work but, they all the same I dont feel any different.However, if I went to my PC audie settieng to check if I am using 5.1, I see I am using 2.1 but still the sounds come from all the speaker because of the speaker itself can change the audio but as I said this is not a 5.1 it is 2.1 because when I test it from my PC for 5.1 I only I can hear the right and left work. WhenI do the test and my right and left works as if the pc telling me, my speakers all of them work as if they are just right and left. So. since my speaker do not have SPDIF is there is a way to make it work ? I do not want to buy a DVD just to connect my speaker to it and then from the DVD to my TV.