I had a fully functional 19.04 machine until I rebooted today. Now the machine boots to a blinking cursor on a black screen. Since pressing the power button results in an immediate shutdown, it appears nothing has loaded.
I see there are a couple of other posts regarding 10.04 and booting. However, I can't try any of the suggestions as these there methods all go to a blinking cursor - booting from HD - holding left shift while booting - booting from a 19.04 USB
System is a Dell 8900 with NVIDA graphics, i7 processor. Had been running 18.04 without problem for a year. 19.04 was installed as a fresh install, not upgrade.
The same thing happened a few days ago but I was able to hold down left shift, get into the utility (not sure what it is called), updated GRUB and then it rebooted.