graphical login never appears

After todays updates (post 7:30AM EDT), booting F10beta no longer presents the
GUI (or any other) login prompt. The screen just seems to toggle its backlight
on and off, but thats hard to tell. I can't seem to flip to a text mode screen either.

I saw a two day old thread that talked about using nomodeset during boot time,
but with this new boot software, I don't even know how to get to a prompt
to allow me to edit the boot lines to give that a try.

Does anyone have any comments?

TIA
Fulko