Ubuntu 9.10 - boot always load to Grub prompt

See Ubuntu Forum's thread: here

See a possible solution: here

Other problems:
- the kernel linux-headers-2.6.31-19-generic doesn't work/cannot boot - currently using 2.6.31-17-generic

Ubuntu 9.10 cannot update

I had trouble updating my Ubuntu 9.10 (Karmic Koala) using the Update Manager. Everytime I run update, the Update Manager freezes on 'Downloading Files...'. I can Force Quit it, but the next time I tried to run the Update Manager again, it says 'Another Synaptic application is already running' and won't let me launch the Update Manager. When I shutdown or restart, a message appears saying "AT SPI Registry Wrapper is not responding" - everytime.

So I googled the problem, and found several links:
- A bug report for the unable-to-update issue: https://answers.launchpad.net/ubuntu/+question/6719
Here, I used Manu Arya's suggestion to comment out /etc/network/interfaces:
> in Terminal, type: sudo gedit /etc/network/interfaces
> comment the following entries, from:
auto lo
iface lo inet loopback
to:
#auto lo
#iface lo inet loopback
- The issue with 'AT SPI Registry Wrapper not responding': https://bugs.launchpad.net/ubuntu/+source/at-spi/+bug/477978
From this, I disabled the AT (Assistive Technologies):
> From the toolbar: System > Preferences > Assistive Technologies
> uncheck the "Enable assistive technologies" checkbox
- Restart/reboot

Now I was able to run the update.

Note:
1. Before I run the update, I did:
> $ sudo apt-get update
to check for new updates (it doesn't install the updates, just updates the update list)
2. Since I did both changes (commenting the /etc/network/interfaces, and disabling Assistive Technologies) before retrying the update, I cannot tell which change solved the problem - whether it's one of them or both.
3. Note that any features you're using that requires Assistive Technologies will be disabled. So I don't know if or why AT is a problem (i.e. why the AT SPI registry wrapper always said to be not responding).