Can't boot or bring up recovery / boot selection after BootCamp assistant formatted drive
I have a Mac Pro 2011 that I've been using to run both OSX (High Sierra) and Windows. Recently the windows install got messed up so wanted to reinstall. I booted into OSX and used the BootCamp assistant as I did the first time I installed. It asked me which drive to erase and use for Windows, so I chose the Windows disk (which had the label of BOOTCAMP). The system rebooted soon after and now it won't boot to any OS and none of the option key boot combination work either. I can't bring up recovery, choose to boot from Mac OS install DVD. I don't even see a gray screen or any logo when it boots up. The mouse lights up when the system powers on, but not the keyboard. Before running BootCamp I had used the keyboard to bring up the boot menu to boot into OSX so I know it was working. I've tried different USB keyboards as well (all USB PC keyboards). I inserted the OSX install disk to the DVD drive (which I had manually eject since I couldn't use keyboard shortcuts, fun) and the disk spins up on boot but then nothing happens.
It would seem that the BootCamp assistant completely messed up the systems ability not just to boot into OSX without intervention, but to even get far enough to respond to key presses and bring up alternate boot options (like repair).
Any advice? Is there any complete failsafe mechanism that would force the system to boot from the OSX install DVD without intervention (i.e. - no keyboard shortcut)?