Basically I got my new computer, installed Windows 7, got all the drivers, got Internet, got Steam, got Mumble.
The thing is, I can hear people in Mumble, but they cannot hear me. When I push my push-to-talk button they can hear echos of themselves or even music I am playing in youtube.
It happens while using the front as well as the rear connections.
And with both, my old (Speedlink Medusa) and my new (Sennheisser PC 360) headset, which were both working fine before.
Also while trying it on a different computer with my two headsets I get the same result, I can hear but not talk.
I have no idea, drivers are updated, there is nothing that could have broken the headsets, …
I am desperate for help.
Got some suggestions already:
http://etf2l.org/forum/support/topic-17996/page-1/
Nothing worked.