Issues with Bose 5.1 setup (no sound from rear speakers)

Hey everyone.

First off, sorry if I’m posting this in the wrong thread or if someone already tackled this topic... just didn't want to be that guy.

So, I picked up some Bose 5.1 speakers, hooked everything up exactly how the manual says, but I'm getting absolutely zero sound from the rear two speakers. It's driving me nuts. I have no clue what kind of sound card I'm actually running—does anyone even know where you check that? And is it even possible that my card doesn't actually support surround sound, even though there's a physical jack right there for the rear speakers? The front three and the subwoofer are working perfectly fine, which makes no sense. I went into the Control Panel, navigated over to Sound and Audio Devices, and messed around in the Advanced Audio Settings to set it to a 5.1 setup, but still nothing...

Sorry if these questions seem a bit amateurish, I'm really not an expert with this kind of hardware, so I'm a bit lost on what to do next. Any help at all would be massively appreciated.

EDIT:

Never mind, figured it out! I switched the configuration to a 7.1 setup and suddenly they started working. Weird, but it works.

So, if you’re telling me it’s set to 7.1, then you're basically blaming yourself again, right?

Do you actually have enough ports tucked away behind your PC to plug in all four speakers (or is it five)?

Look, if we're being technical about it, the setup is technically wrong because I don't actually have all eight speakers hooked up, but at least those two rear ones are finally making some noise. On the back of my PC case, I've got those three multicolored jacks—you know, the black, green, and that weird light purple one—for the front and rear channels.

What I’m trying to get at is that those two rear speakers might actually be doubling as your side channels in a 7.1 setup. In that configuration, you don't really have dedicated rear surrounds anymore.

But hey, if you’ve already run the tests and everything sounds solid... then honestly, you're golden.