So, the audio ports on the integrated sound card don't work when the headset connected and the USB sound card removed.
I think this is
normal behaviour, isn't it
?
When somebody uses headset he doesn't use external speakers at the same time (he doesn't have more than 2 ears) and since the headset has microphone too, then no need for an external mic either. I suppose they are disabled by default.
However, if you still want to troubleshoot, you can do this (if not already done):
1) check the audio settings in Windows (maybe there is an option to enable the audio ports when the headset is connected)
2) install the latest drivers for your
motherboard/sound card
3) install the latest...