I made a little progress. I downloaded ATI's proprietary driver (version 8.561), and installed it from single-user mode.
When I next booted, X didn't show me the white screen, but instead showed me a dialog box (grey on a black background) stating that there were problems with starting X, and it gave me several options. I think they included reconfiguring X, starting in low-graphics mode, and one other.
Anyway, I believe I started in low-graphics mode, just so I could log into my deskop. Then I went to the restricted drivers gui. It showed me a proprietary ATI driver being available, so I selected that. I was hoping that it would give me better luck than my manual installation of an ATI driver, mentioned at the beginning of this comment.
Sadly, when I rebooted, I got the same experience: the X dialog giving me a few options of how to deal with its inability to start.
I made a little progress. I downloaded ATI's proprietary driver (version 8.561), and installed it from single-user mode.
When I next booted, X didn't show me the white screen, but instead showed me a dialog box (grey on a black background) stating that there were problems with starting X, and it gave me several options. I think they included reconfiguring X, starting in low-graphics mode, and one other.
Anyway, I believe I started in low-graphics mode, just so I could log into my deskop. Then I went to the restricted drivers gui. It showed me a proprietary ATI driver being available, so I selected that. I was hoping that it would give me better luck than my manual installation of an ATI driver, mentioned at the beginning of this comment.
Sadly, when I rebooted, I got the same experience: the X dialog giving me a few options of how to deal with its inability to start.