Desktop sometimes doesn't load


I have a strange problem that may be related to the ATI graphics card driver, and I would appreciate any pointers on what to look for.

My configuration : 11.2, gnome.

When I turn on my computer, the desktop sometimes fails to load completely, and I am left with the green wallpaper from GNOME and nothing else (no mouse cursor, no toolbar at the bottom, no icons…). If I reboot, things are usually ok, but it can take several reboots for the desktop to finally load (??).

Also, and possibly related to the same problem, it did happen a few times that at shutdown, instead of directly shutting down as it is supposed to do, a panel popped up with my name and three options (Suspend/Restart/Shutdown). Clicking on shutdown or restart didn’t do anything. Only suspend seemed to shutdown the computer (??).

Any idea what’s that all about?.. Thanks!