Black screen on boot after upgrade to Karmic

[Dave M G]

Ubuntu Users,

I upgraded my laptop to Xubuntu Karmic today. It's a slightly older
laptop, but was rock solid with Jaunty.

When I boot, it gets to the end of the boot splash, and then the screen
goes black.

Of course I looked on the net and found out about the suggested problems
with xorg.conf, disabling the splash on boot, and using vesa drivers.
None of those have helped, though.

Here's the odd thing. If I select to boot into recovery mode, and then
select to "resume normal boot", I can log in at a command prompt. Once I
log in, I can then use the command "startx", and Gnome boots up fine.

Once I've got that far, I can log out, log into an Xcfe session, or
whatever else.

But if I reboot, I'm back to the black screen.

So it seems it's just something about the boot process itself, at the
moment of switching into graphics mode where the system chokes.

Any suggestions on what I might do?

Thank you for any advice.

-- 
Dave M G