I have seen this often where the problem is a bad ground, even for a digital line like USB.
The question is how to test - The easiest thing would be to eliminate your OS. Download a bootable linux CD, they should all have the realtek drivers. If the problem persists, it is most likely hardware.
Reply to MDSIU, he said headsets, so... I could be wrong. if its just one, thats the thing to try first.