Most generic USB sound cards of that era (and even many today) are "line-level" devices. They output a weak signal meant to be fed into a powered speaker or a dedicated amplifier. If you plugged high-impedance headphones (like Sennheiser HD600s) into them, the volume would be anemic, and the bass distorted.
To avoid conflicts (BSODs or audio dropouts), follow this protocol: ab13x usb audio driver best
(Windows):