Ugh. HDD death forced me to get a new drive and reinstall Windows. I have successfully installed the drivers in the KFU zip which I downloaded fresh today. Device Manager has no unknown devices, and I have an Android ADB interface in the list.
Right now it is plugged into the computer and the Kindle is displaying the "you can now transfer files from your computer to Kindle" screen with the Disconnect button, but it's not showing up. It also is not showing up in the Disk Management area in Computer Management. Also, KFU says ADB status is "offline" and boot status is "Unknown".
This is Win7 x64. Any ideas?
edit: fixed it. Unplugged the device and installed the drivers, then plugged it in. Voila, mounts in Windows.