If your sound card is no longer operative, it will not output any audio signal. The USB port is for give power to the internal amplifier, and the audio goes through the 3.5mm jack. You should get an USB sound card (and a USB hub, because laptops don’t have many USBs), so you can get your audio signal through this card, instead of the integrated one. They’re quite cheap, around 15-20 bucks a basic, but decent one from any trusted brand, like Hama, Trust, Creative… The usual suspects that give a good sound quality with proper grounding for the electric noise… Not the crappy non-branded ones from Amazon or Aliexpress… They’re 5-10 bucks, but the sound quality is terrible, hearing all kinds of buzzings and hums, yuck!