I can't seem to use my plug-in microphone?

[VirusChris]

I'm having a slight problem here, I just turned off my built-in microphone so I can use my Yeti USB plug-in microphone but it doesn't look like I'm using it or its own.

I went to Audacity to test out my Yeti microphone but nothing was recording when I spoke into it and I double-check my Sound to see my "Microphone / Line In" is set to default but I've notice the bars on the right of it are gray and my "Microhpone / Array" is gone when I went to disable it.

My laptop said the USB connection was installed successfully but I can't use my microphone on my Dell Inspiron 1545 laptop and I'm wondering if I put it in the wrong USB slot or I'm missing something or its a problem regarding my laptop. What should I do? How do I setup my Yeti microphone so I can use it if it doesn't work by just plugging it in.

PS: Also, what do I need to do to turn back on my built-in microphone? This is just in case I can't get my microphone to work and when I need to put my Yeti microphone away.