Hi Matej,
This pc I'm using it runs  windows xp, It's not my own pc .. i've asked to change to lin and awaiting for the ok.
The pc I've had the problem instead is my home pc.
I was courious to see the new fedora9 I've burned the live cd   Fedora-9-Preview-i686-Live.iso
Immediately after choosing to boot the live distro appears a list of     "Buffer I/O error on device sr0"  and than the monitor go in a power-saving state and the system remain freezed.
As I'm using a live-cd I don't think I can recover the Xorg.0.conf

I download and try to install the dvd version and let you have news... because unless there're options to boot not graphically the
Fedora-9-Preview-i686-Live.iso  I'm not able to boot it.

I'm testing also other distros .. I've noticed something interesting: al distros based on xorg-server 1.3.0 and with ati drivers version 6.6.3   my card worked perfectly (Fedora8, Slackware12, Debian 4.0_rc3, Ubuntu 7.10 ...)  and at 1600x1200 resolution.
Instead there are problems with the new xorg-server and/or xf86-video-ati-6.8.0 driver
For example yesterday a friend passed me a dvd containing the updated slackware-current and at the evening, while awaiting for possible answers, I've installed it. It uses xorg-server 1.4.0.90  and  ati-6.8.0   at the startx it freezed.  I've recompiled the old ati-6.6.3  but obtained the same result .. freezed. At the moment I've just the Xorg.0.log  of that slackware-current .. I saved them.  I don't know if in the meantime I download the fedora9 dvd they can be helpful for you.
In department I've another pc with my same ati card and downloaded other recent distros, all using recent xorg and ati .. all freezed.
is it possible that it can be a xorg-server problem??

I'm at your complete disposal, let me know if I can post the slack Xorg.0.log .. otherwise I'm downloading the fedora dvd .. I'll need 6 hour to finish downloading it.

Thanks a lot for your help,

Nicola

PS:  I send you that files ...   xorg.conf, Xorg.0.log  (they are slackware ones, but they are the ones I've in the immediate)  .. when I'll have the new ones I'll post you that ones too using the bugzilla.