herci/draiveri uz ubuntu

man ir ubuntu 6.06, probleema ir ar herciem. no sakuma radija ka ir 61Hz manuaali nomainiju uz 85Hz (sudo gedit /etc/X11/xorg.conf) bet vienalga nejut nekadu izmainju
vai butu janoinstale kadi draiveri videokartei (man gf 6600) meginaaju ar      sudo apt-get install nvidia-glx bet tur parada:

Reading package lists... Done
Building dependency tree... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 nvidia-glx: Depends: xserver-common (>= 4.0.3) but it is not going to be installed
E: Broken packages

vel novilku draiverus no nvidia majaslapas bet kad to instalee tad parada shitadu :

ERROR: You appear to be running an X server; please exit X before
        installing.  For further details, please see the section INSTALLING
        THE NVIDIA DRIVER in the README available on the Linux driver
        download page at www.nvidia.com.

lasiju to readme kas tai lapa bet neatradu kaa tad izrubiit to X server
varbut kadam vel ir liidziigas problemas bijushas ?