Ubuntu 9.10
2.6.31-16-generic
Acer Extensa 5620Z Laptop

I have been running Karmic Koala from a fresh install for the last several weeks with NO problems.

Tonight, I ran the update. While it was running, I locked my screen. I came back later and unlocked the screen and the update had completed and was waiting to reboot. I answered the prompt indicating that I would reboot later, closed all open screens, and then selected the Ubuntu menu reboot option.

The boot-up got as far as displaying the Ubuntu circle, but no progress line. Eventually the screen went black.

I power off and when I turn the machine back on, I get the grub menu. If I select recovery mode, I see:

Gave up waiting for the root device. Common problems:
-Boot args (cat /proc/cmdline)
- Check rootdelay= (did the system wait long enough?)
- Check root= (did the system wait for the right device?)
-Missing modules (cat /proc/modules: ls /dev)
ALERT! /dev/disk/by-uuid/##### does not exist. Dropping to a shell!

Using a 9.04 Live CD, I am able to use GParted to see that the UUID in the Alert matches the UUID for the sda1 partition information.

How do I correct this problem?