Can't boot notebook from SSD

[MR ZenWiz]

I know this has been around, and I've posted before when I had this
problem with my desktop boot SSD (which was solved - it needed the
UEFI boot space at the front of the drive).

I was able to do a near-complete install of Xubuntu 16.04.2 on the
drive using my USB flash drive.  All went well until I had to reboot.
All I get is the flashing undersccore cursor.

At first I didn't even get the grub screen, but I made some
adjustments and that at least comes up.

Adjustments:

1. Added the UEFI boot space and reinstalled.  Note: I do my own disk
configuration - 1MB UEFI boot partition, swap space and the rest goes
for /.

2. Went through the boot prom to add the SSD to the list of bout
options (this stalled me for about an hour, but I finally figured it
out).  For some reason, this PROM can't figure out which drive to boot
from and get it right, so I have to tell it.

3. I even tried disabling the UEFI boot in the PROM - no change (that
works both ways with the hard drive).

I'm not sure what's next.  I can run the mem test, which I did because
I also put in 16GB of RAM - that works flawlessly with the old boot
drive.

It boots up to the grub meu, I type return, and the screen goes
completely black for a second, then the cursor comes on and nothing
happens until it drops into BusyBux, which tells me nothing.

The current boot disk is a Seagate 500GB hard drive.  The SSD is a
Toshiba OCZ 240GB SSD.  The notebook is an ASUS N75SF.

What am I missing?

Thanks.
MR