Audio not working on laptop

When using my laptop and a second monitor my audio stopped working on zoom. IT did trouble shooting and even reset zoom. Still not audio. They told me to buy a separate microphone and plug it into my laptop usb. I tested zoom via my cell phone. Once I did that, I could hear audio via my phone AND my computer. Turned volume off on phone and still heard it through my computer. Contacted IT again and they still said I needed a new separate microphone. Can someone tell me how to get audio working on my laptop with zoom? TIA