Hold your horses guys, before you all go buying new interfaces and crap. I almost decided to buy a new interface too until I tried out this:
It isn't a guaranteed fix for everyone for some reason, but it worked for me and I've tried like, every single suggested thing on every thread about this topic. This did it. I can see the green bars filling in the recording devices tab when I tap the mic, Audacity doesn't give me an error on start up anymore. I gasped in complete joy and surprise. It's worth a shot for you all.