This machine is mad quick

I purchased this desktop on the 22 of Aug, and I spent a few days working with Acer to try and fix the Bluetooth problems (The signal was weak - dropping connection less than a foot away). With no available fix, I returned the computer on the 28th; and, I exchanged it for another one. That said, I should have trusted my gut, and went with a different computer all together, because now the second computer (8 hours out of the box) can't recognize my USB microphone. After some troubleshooting with no fix - i'm back on the phone dealing with Acer support.