Put in your service tag there to get to the documentation and drivers for your machine. Sorry, you need to do this since there are too many versions of that model and the service tag will nail it.
I'm running a Dell Optiplex Gx 270 with a soundmax integrated digital audio version 184.108.40.20600 soundcard on a 2.26 GHz desktop with 256 MB Ram (It's my work PC, lol).
A) Does this soundcard support surround sound?
B) Will a driver upgrade work to get it to support surround (5.1) sound?
C) Where can I get said driver?