Question headset audio card vs dedicated usb card

[Ghilgamesh]

Hello. My lenovo notebook had a mobo malfunction and I couldn't get audio signal from my 3.5mm jack. So I purchased a steelseries siberia v2 USB headset (which had it's own audio card) and I was happy. Until some days ago, when my headset failed me and I had to replace it. But this time I went a different route: I got an Asus Xonar U3 USB audio card and some normal 3.5 mm jack headphones. But I can't get an audio signal from it. It says "no speakers or headphones are plugged in."
Why is it that everything is fine with the steelseries headset and not the usb card+normal headphones?
Is the internal circuitry different between these audio cards?
Must I get the same steelseries siberia v2 usb headset or will any other usb headset work? Thanks for your help.

 

[hang-the-9]

Does the computer see the USB card properly in device manager? Is it set as the default audio device? Did you test the headphones on another device to make sure they are good?

 

[Ghilgamesh]

Does the computer see the USB card properly in device manager? Is it set as the default audio device? Did you test the headphones on another device to make sure they are good?

yes. yes. and yes.

I have some updates: after messing around with some driver installation, I ended up in a boot loop. I was then forced to use f8+ last known good configuration which, to my ultimate surprise, gave my sound back. I know have sounds in my speakers (which I thought were burned or something cause they were not working) and I also have sound from my xonar u3 card. but there is another problem now: when I try to install the amd radeon software, this software begins by unistalling old drivers, after which my sound stops working again. So now I have sound, its perfect, but I have no video drivers for my 8500m gpu.