nVidia proprietary drivers leaves PC ususable

[Sebi Kul]

Hi all!

For a better understanding I will separate my problem in two fragments, 
both of which converge with the same problem.

The first time I had this problem was a couple of months ago (while 
using Ubuntu 10.10), when upgrading the nVidia proprietary driver using 
the "~ubuntu-x-swat" ppa. The first time I booted after the upgrade I 
found my screen with an image with the nVidia logo, and a line of text 
saying "nVidia BETA Driver". At this point, nothing works, not even CTRL 
+ ALT + F1, all I can do is restart using SysRQ + B.
**This "screen" appears a few seconds after the Ubuntu splash screen 
disappears

I managed to solve this by entering into the grub list, and use a 
fail-safe X session to use ppa-purge to downgrade the driver back to the 
stable one (available on the repositories)

The second time this happened was a few days ago, when I upgraded to 
Natty (clean install). As usual, I installed the propietary drivers 
using jockey (known as "additional drivers"). I had two optios, nouveau 
or the propietary one. I of course chose the last one, to get the best 
out of my video card.
When I booted, I encountered my pc unusable. As I did last time, I 
started a fail-safe X session, removed the nVidia proprietary driver, 
and installed nouveau, just to be able to use my PC.


I wanted to know why this is happening. I tried everything I know to fix 
what was causing this issue, regenerate the xorg.conf(nvidia-xconfig), 
remove nouveau when installing the proprietary driver, but nothing 
solved it.
**Please note that I can't get to nvidia-settings, as I can not boot 
using the nVidia driver (hence, I can't configure it).

I also cant debug anything, I don't know where to look or what to look 
on the logs. I can't get to a login prompt before or after this screen, 
it appears too fast, and when it does, all I can do is reboot

I have a nVidia GT220 PCIe (active), and a nVidia GForce 6150LE (inactive)
**This happened with both video cards

If you need a to see how this "screen" looks, please let me know, so I 
can do it only once(I can't get a screen-shot, I would need to reinstall 
the proprietary driver, boot up, and take a photo of it).
If you need more information about my hardware please, just ask.

Thank you all for your help!