Stuck in fastboot, and unknown USB device.

I would really appreciate it if someone could help me. I tried to root my first gen kindle fire using KFU 0.9.9, but it wouldn't work. I tried using super, and it worked right away. I wanted to put a custom recovery on it so I could try to add an Android ROM to it. Using ADB, I got it into fastboot, but when I tried to load the custom recovery, it just said waiting for device. I unplugged it, switched USB slots, switched USB cables, restarted it, plugged it into the charger and back into the computer, but nothing works. My PC won't even recognize the device. In device manager, it shows up under "Universal Serial Bus controllers" as "Unknown USB Device (Device Descriptor Request Failed). If I try to type anything into ADB, it just says "waiting for device". I'm at a loss. Please help me, or guide me in the right direction, but please don't recommend KFU. because I cannot get that to work at all. Right now, the device is just on fastboot mode, and won't do anything else except turn off.

TL;DR: Rooted my 1st Gen Kindle Fire, got it stuck in fastboot, and my PC only recognizes it as Unknown USB Device (Device Descriptor Request Failed) under "Universal Serial Bus controllers" in device manager.