I added a new drive to my system because the old one was full and stopped. I installed 12.04 at the same time, onto the new drive using a flash disk while off line.

The system performs fine on 12.04 from the flash disk and it booted from the new drive OK and I was able to recover all my old data.

The updater suggested that I update, so I went ahead and did so. At the end of which it wanted to reboot. I went ahead but on reboot I get to the log in prompt and then the whole system crashes. It tries to recover and then performs a bug report during which it tells me that a whole bunch of files are out of date (these would be the new ones I just updated!) and the screen goes black. Game over.

I've tried to reboot several times ... same result.

I can boot off the flash drive OK.

How do I restore the system I had before the update, without over writing all my hard earned recovered data? Or how do I identify the "new updates" that are causing me grief?