I have 5 speakers, and a 5.1 analog audio card. I was wondering if there was any way for me to amp these speakers (it's just the speaker with wire, no built-in amp, volume control, etc) without buying a new receiver.
I have a receiver now, and it can amp my speakers, but it only does Stereo through analog, and I can only do Stereo through SPDIF
Unless you have a couple of additional stereos with analog input lying around and you want to combine all of them together, you're better off just sticking with L/R channel stereo. Depending on your budget, you could maybe start with an upgrade to 2.1 channel; get yourself a cheap powered subwoofer. Even doing that may be an improvement over plain stereo. But as it stands, you're not going to be able to do anything without spending money for more equipment, unless you happen to have individual stereos lying around the house. (I've done that before and arguably, it's better than nothing, if you have the gear and the space).