Problem with channel balance (or rather strange response)

Hello,

After searching and not finding my specific problem in this section, i post this:
Did a fresh Windows 7 ultimate x64 genuine install about 3 weeks ago and everything was fine. I was using Creative Sound Blaster X-Fi USB to great effect, until one week ago when boom, lightning and smoke from the amplifier AND the sound card... The sound card and all USB ports fried.
Repaired by installing PCI USB adapter and switch to Realtek HD Audio. Soon after i noticed there is a VERY strange problem: left channel is a lot louder than right and more than that... most of the bass and low mids are on the left and most of the high mids and treble are on the left. I tried tweaking the balance and when i go maximum left the channels unite and everything becomes mono. When inbetween maximum left and middle, the sound on the right becomes a bit garbled.
Here's what i did:
- removed Realtek driver
- installed GamerSpirit custom driver - sounds impressive but the problem remains
- left only the default Windows driver - problem still there to a lesser degree
- disabled Realtek sound - installed a CMI8738 card - still the same fault plus the low audio quality of CMI
- replaced with Sound Blaster Live! card - mindblowing, in some respects surpasses the X-Fi but the awkward partitioning of sounds is still there
- followed advice on the net and did sfc /scannow to check windows - checks fine
- also tried winamp, foobar2000, etc, does the same, even youtube sounds the same
I don't know what to do...
"it's not the fall that kills you, it's the sudden stop at the bottom" as such could it be the audio service was ruined when it violently stopped working? And if it is how can i mend it without a full reinstall of the OS?

Thanks for the reply. Actually i don't have a speaker system right now, i'm still rebuilding the fried amplifier . I have about 3 pairs of headphones however, that (aside from small differences) all display the same problem.
I have yet to test a simple stereo (non multichannel) soundcard...that could force the Windows audio mixer or whatever is causing the problem to reset itself to simple stereo. Unfortunately i have yet to find such a card still supported in Windows 7 x64.
What seems to actually be happening is Windows thinks the left channel is... left or rear left and the right is center, judging by what is produced in them. To put it simply, any voice is only in the right headphone, and any high pitched sound is only in the left headphone.

Naturally, i am setting it as such. I also did that from any control panel of the cards themselves the ones that had any, but switching in between modes changes nothing, possibly because regular mp3 files are not multichannel.
Moreover with the non-official (and only) driver for the SB Live i can also select individual outputs as the only playback device in the Windows audio properties. Setting the master mixer as the output it simply adds echo, probably as what should be rear channels are mixed in with the front.
As this is a rather awkward (if ingenious) driver i might switch back to Realtek HD audio to eliminate the driver as the culprit, but from what i found on the web the Realtek driver is even after so many years far from bug free or stable.

Update: problems seems solved at least for now after, in the KX driver for Creative SB ticked the compatibility option Pan/Balance followed by a restart. As far as i know it enables the "classic" hardware-based balance control.
This would point to a software glitch in Windows although i'm not sure it's just software. As of today the computer no longer remembers it's BIOS settings nor the time, but strangely remembers the date, even though the battery is just fine. This is very nerve-wrecking as i have to redefine the RAID function every time, but it's for another topic entirely.