Okay, I have recently bought Philips MMS460 5.1 PC Speakers for my PC from Hong Kong. I currently live in Canada. I have bought an adapter that switches the voltage, so that is not a factor regarding the speaker problem. My problem is, when I plug in the yellow/orange, green and black 3.5mm jacks, there are either sound in the 2 FRONT speakers, sound in the 2 BACK speakers, all 4 FRONT and BACK speakers, or just the center speaker and the subwoofer. Overall, all the speakers are working, but I can't seem to get them to work "together". What is the point of buying a 5.1 if the woofer doesn't work together? Please help. Is it because of a sound card? I have tried all the combinations with the 3.5mm jacks (yellow/orange, green, black). All I need is for all the 5 speakers and the woofer to work. Any help would be greatly appreciated.