Tablet displaying Android with a yellow hard hat "Wait for Download"

[Kage_]

I just picked up a Nexus 7 1st Gen WiFi 16GB running 4.1.1 and all was working well on it. I configured it, played with it a bit,even rebooted it once and then left it to charge for a while. I then decided to unlock the bootloader and root it. I enabled usb debugging, connected it to my laptop and issued adb reboot bootloader from my platform-tools in my Android sdk folder. The tablet rebooted, but instead of booting into the bootloader I got a message saying No USB Cable Connected with a question mark and an unknown device in Windows 7 Pro x64. Using NRT I found the correct driver and now I have an android with a yellow hard hat on it with a message saying Wait for Download. Power + Down doesn't get me anywhere except the same messages. Power + Down + Up doesn't work either. Now I'm stumped. 'ADB devices' doesn't see it nor does fastboot. Anyone have any pointers?

Kage_