Does anyone knows how to swap the channels of the front panel audio only. I found some solutions to swap left-right in general. But my problem is, that the output from the backward jack is correct and the front panel audio is reversed.
To me this strongly suggests an incorrectly wired jack or the pin header connector. I would not expect this to be software related.
Regardless of the cause, the fix is pretty simple if you're happy opening up the computer. There should be a 4-pin female connector coming off the headphone jack, connected to the motherboard (or the sound card - if sound isn't onboard). Occasionally — when the manufacturer is a sadist — these connectors will be individual.
Anyway, the game is simple: reverse the connector(s). They need to plug into the same pins, just the other way around.
Very occasionally these cables are part of a bigger-than-4-pin block. These carry other things (like USB, microphone, etc). In this case it's not suitable to reverse the block and it's likely that won't be possible. You're left with two choices:
Both these options could invalidate your warranty if something goes wrong.
If when you look at things this 4-pin thing I'm warbling on about doesn't exist at all or is part of something else I haven't described, get the motherboard make/model and get a manual for it.
Every motherboard I've ever owned (and I'm in double figures) has had details about how the audio is wired in. Just note that this has nothing to do with the "PC Speaker" header; that's just for beeps and squeaks.
Oh and if it's a new computer (bought from somewhere who have real, on-site people) you could take it back in and have them sort the connector. If it's a box company, you'll be without a computer for weeks so I'd just do it myself.