Re: 8800 GT problem
Please read the sticky threads on how to report problems.
With a nvidia bug report (or at least a Xorg log file)
we could help you solving this problem.
Probably you just have mixed up drivers and libraries now,
because you should _not_ install drivers by hand on ubuntu.
Remove the manually installed and the ubuntu driver,
read the sticky thread on how to install recent drivers
on recent distributions, follow the instructions, try again
and if it still doesn't work: provide a bug report file.