Bootcamp fail stuck at no bootable device (hold option not working)
If you reset the NVRAM, the Mac should find the first Mac OS bootbale volume and start.  If not, you can power down and try the option key again. 

If that fails, your Mac boot volume is broken or your hardware is broken. Try booting to Recovery HD or internet recovery at that point to reinstall your Mac OS on top of your old Mac user and data.