Why do you think it could be a memory resource problem? Just wondering. I would ensure that the cable from the speakers to the sound card is not frayed and is in all the way. You've got in the right port, right? When all the ports are the same color or when I can't tell, I just play some music and try ports. I would try updating the drivers of the Sound Card... If that doesn't work, try switching speakers just to see which one is bad.
My speakers almost always do not work properly. The sound is distorted and "clicks" a lot. I am not sure if it's the speakers or the sound card. Sometimes the sound is fine but most of the time worthless. It seems to be a memory resource problem? Is there any way to test for this. I have checked my drivers and everything is working properly. I have a Dell Dimesions 4500, 1GIG RAM, 2GIG Processor, Win XP, the sound card is a Creative SB Live Value(WDM), the driver is version 5.1.2535.0 (From 2001). The speakers are older Altec Lansings I got from Delkl back in 1999.