How can I uninstall the NVIDIA official driver (or any .run package)?
 

I downloaded it from the nvidia web site, it's NVIDIA-Linux-x86-1.0-9742-pkg1.run and you execute it with "sh". I installed it, and now I need to install one from a repository ('cause this one didn't work). But I don't know how to uninstall this type of package.

Run the Nvidia installer again, and use the '--uninstall' option. For example:

# sh VIDIA-Linux-x86-1.0-9742-pkg1.run --uninstall

And if I installed the one from the repository, will I have problems when removing the official driver?

Yes, some of the same files are involved. To insure that everything is returned to its proper state, I suggest (as root):

1. Change to text mode: telinit 3
2. Remove the repository version: rpm -e xxxx yyyy
3. Remove the official version: sh ./NVIDIA-Linux-x86-1.0-9742-pkg1.run --uninstall

You should be back at the original configuration now. If you want to use the repository version, re-install it, and change to the X runlevel (telinit 5).