Hi, I order a 5.1 speakers before but I just find out that my desktop sound card is for 2.1, right now I just thinking is that possible I can change the sound card ? In the back of sound card are have 3 ( they are green, pink, and green) hole for those plug and the 5.1 sound card need 4 (green , pink, red/orange, black) so what should I do ?is that mean I can only have 2.1 sound card ? -.- and my desktop is dell dimension E310.

As it looks like you have an integrated on-board sound card, you would need to buy a sound card that plugs into the mother board that is 5.1 compatible

So you would be purchasing a 5.1 or 7.1 sound card and install that and disable your on-board sound

You can plug in Green color plug to your PC's green color port . You can hear the sound from your speaker but only support 2 speaker .

If you want 5.1 , you need to buy sound card. You can slot in the sound card on your PC at PCI slot.


Best Regards,
ABB

Another option is to see if your on-board sound supports Dolby Digital, it will send surround sound encoded signal that I would think most surround sound speakers would understand(my little wal*mart duro brand 5.1 speakers support it.)

Can't remember the setting exactly, but it was on my old MSI K7N2 Delta ILSR. Looking at the page it just says
"Audio Processing Unit(APU) encodes audio in Dolby® Digital 5.1 format for full surround sound effects"