Hi, it always worked fine, i plugged something into mic socket and pop up appeared then i chose line in (plugging in a guitar) and that was it. I also could switch under volume properties between microphone and line in and it gives different sound behavior. Yesterday, i checked stereo mix instead of line in and horrible sound came out like feedback, so i switched to line in but it works now like it is microphone input with low impedancy, so i hear lot of cracks, pops and buzzes having guitar connected, exacly like it was while choosing mic input. Other thing is, when i switch to mic input it didn't work at all.
I have ghost image of working system, did restore but it didn't work out.
May sound card be broken suddenly? Reinstalling everything didn't work either.