Windows – Sound only from the right speaker

I'm using S/PDIF and I only get sound from the right speaker plus the subwoofer.

I've checked the balance settings:

Adjusting #1 does nothing. Adjusting #2 affects the right speaker.

I've also tried:

• Switch places for the speakers to make sure that both works
• Switch the cables

Same thing. Only audio from the right speaker. So I'm quite certain that it's not a speaker problem but how windows sends the audio (or sound card problem).

Update

Here's the strange thing: My volume knob which comes with the speakers have a headphone (3,5mm) jack. If I connect my head pones to that jack I get stereo in them. Same thing if I connect my headphones to the front computer jack.

Are there a Windows 8 setting which configures the soundcard to send audio as 5.1 or similar?

Update 2

I've bought a new sound card (Asus Xonar D2X). Almost the same thing. Now I only get sound from the left headphone.

I've also bought new speakers (Edifier). Same same.. 🙁

Update 3

If I connect my head phones to a 3,5mm soundcard jack I get stereo.

Update 4

I've now tried with a "regular" cable from the computer to the speakers. I've made sure that a 2 speaker system is selected. Still no sound from the left speaker.

I've tried two different speaker systems and two different soundcards (the built in Realtek card and my new PCIe asus one).

I've also had the same problem in Windows 7 and Windows 8.

Hence the only thing left is the mother board, right? But before I accept an answer how could the motherboard affect the sound in such way?

Update 5

Ubuntu and Fedora gives me the same errors when I try to boot them (burned a live CD for both):

Something like:

GPU Lockup switching to fbcon
[...]
PFIFO playlist update failed

So that makes it a bit hard to try the sound using Linux.

Update 6

I tried the new speakers with my laptop and got the same result. So I tried my old speakers with the laptop and both works (seems like one of the speaker cords were loose, I had to wiggle it. I blame my son for that ;)).

The new speakers have red/white connector. And I tried to switch them resulting in the same speaker only getting sound. So the computer seems to send stereo all right.

Next test was to switch the speaker cables on from the bass unit. Then the sound shifted to the other speaker. So it seems like the hardware in the bass or the speaker connector is broke?

So all of this just seems like a circumstantial mess 🙁 First that the old left speaker got played around with by my son (resulting in me buying new speakers which didn't work either). And then a new soundcard. Guess I'll go and return the new speakers then.

Update 7

Heh. I still get problems. Everything have now been switched and I find it hard to believe that my third pair of speakers are broken too.