How I unbricked Kindle Fire (first gen) after too many login attempts:

I used windows XP 32bit for this

Get the kindle fire untility (KFU) v0.9.6 or above here:
http://forum.xda-developers.com/showthread.php?t=1399889

If your kindel doesn't show up in device manager as an Android Phone with the ADB drivers, then run the driver install from the kindle fire utility folder you just downloaded

If the drivers fail to install, check out this guide:
http://www.jayceooi.com/2011/12/13/how-to-install-kindle-fire-adb-usb-driver/
The android_winusb.inf file in the KFU folder has already been edited with the correct location, so that part is not required.
Edit the adb_usb.ini like it says and then update the driver again.  

Now that the correct driver is installed, KFU should be able to work its magic.  Use this to Root & install TWRP & FireFireFire.

Custom rom I installed:
I used the CM10.1/SGT7 rom with Android 4.2.1 from here:
http://rootkindlefire.com/kindle-fire-roms/cm10-1sgt7-rom-for-kindle-fire-tablet-ui-optionandroid-4-2-1/
And install the correct gapps from here (install from TWRP):
http://wiki.cyanogenmod.org/w/Gapps