My PC will not start up. I get emergency mode.
journalctl -xb does not show anything strange except one thing:
Failed to mount /proc/bus/usb
mount: mount point /proc/bus/usb does not exist
/etc/fstab has
usbfs /proc/bus/usb usbfs defaults 0 0
So remove it from /etc/fstab.
So it is not supposed to be there in a standard installation?
No. It is not present there in a standard installation.