Well, that may be the point, it may not be fixable as it is now. It's like trying to have a quiet conversation at a rock concert
You want clear quality but your computer sounds like it's loud enough to be annoying, so your mic will probably pick up noise no matter what settings we change.
Do you know what parts of your computer are being so loud? Case fans, CPU fan, PSU fan?
Listing out your hardware would be helpful if you can get it also.