I pulled out my old Altec Lansing ACS495 speakers and have been trying to use them with my Alienware running Windows XP.  Unfortunately the software to manage the speakers via USB only works with Windows 98 (kinda tells you how old these are).  However, in my latest Google attempt I found this thread, which reminded me that I can at least get the speakers into surround sound mode by pressing the center button and holding it for about 2 seconds.  They do in fact sound *much* better that way...