i suppose i spoke a little too soon when i suggested an a/v receiver...
i still agree with the diagnosis (lack of power) though.
yes, an a/v receiver can power that many speakers.
no, after thinking it over more it will not work for you.
the problems i see are as follows:
- a/v receiver outputs connect to either a bannana clip or bare wire lead. computer speakers have phono plug ends typically.
-a/v receiver outputs (and HT speakers) have two wire leads, i dont think pc speakers are two channel.
-RF computer speakers typically have a special cable (for control knob)
i probably shouldnt have suggested the solution in the first place but i wasn't thinking apples to apples as i should have been.
you can probably get at least a 7.1 system (maybe more if you dont overload the maximum w per channel) hooked up with a pci sound card that has an extra connector pin for power.