dtr

I am using the 5.1 set with a Soundblaster Live 5.1 sound card on Windows XP. My question is this: which input do I use to connect the center channel speaker, as there doesn't seem to be a clear choice. Also, how would I go about hooking up my videogame consoles so that I have full surround? The method I tried (using a Y cable and plugging that into both the side of the control center and into the Line-In jack on my sound card) resulted in sound only coming from the front speakers and the subwoofer. When I play music on my computer however, sound comes from all 4 speakers (as I said, I don't know where to plug in the center channel). Am I better off upgrading my soundcard to an Audigy platinum, so I can just use the panel it comes with to plug things into?