[PLUG] HELP! Totally hosed my laptop! X won't start!

[John Jordan]

I got a notice on the Scriibus e-list that there was a new version, 
which included a new repository for .deb files. Thinking that it might 
help me get the latest version installed on my Ubuntu-64 Breezy 
laptop, I opened Synaptic and tried to add the repository. That 
didn't work, but in the process I noticed that there were additional 
repositories for Ubuntu Updates and for Security fixes. These 
repositories had not been enabled. I wondered why I had not been 
seeing the little "new updates available" icon for a long time. So I 
added them, then updated Synaptic. Following that I saw the "new 
updates available" icon. I closed all running programs and then 
clicked on it. It listed 230 packages. I decided to go ahead and let 
it do the updates. BIG MISTAKE!

Fifteen minutes later it finished. I decided to reboot just to make 
sure everything was cool. Normally when my computer boots it 
lists all the things it is doing, but it does so in "normal" mode or 
something. This time it listed everything in like "verbose" mode. 
Miles of messages scrolled past. And then, just as I thought it was 
about to go graphical, I got a horrible error message: FAILED TO 
START X WINDOWS SYSTEM, Unable to locate NVIDIA driver.

I found myself at a command line. No GUI. Note that I installed the 
Nvidia proprietary driver some time ago, and it had been working 
fine. But I also noticed something in one of the 230 packages 
referring to Nvidia. Undoubtedly that is what caused the current 
problem. I wish there was a "rollback" option to undo the updates. I 
tried rebooting one more time, but got the same results.

If I were a command line guru I bet I could fix it. But I know next to 
nothing of the command line. Plus I have no idea why the Nvidia 
driver is not where it is supposed to be, nor do I even know where it 
is supposed to be or what it is called.

At this point I am thinking about my old hard drive. Those who were 
at the last clinic may recall that I replaced my hard drive then. My 
old one is sitting here and it would work fine if I just stuck it in. I do 
have some new homework files created in the past week or so, but 
I bet I could figure out how to mount my other USB drive that I use 
for backups and copy them over. Then I could copy them back to 
the old drive after swapping. But that is not the best solution. A 
better idea would be to fix what is wrong with the "updated" 
installation. 

Anyone have any ideas where to start? I'm really pretty desperate 
here!