My Ubuntu suddenly got this trouble: after one time shutting down, I noticed that there were lots of lines running on the black screen before the computer was completely off. On the very next time I started, I only could get the log in screen. I tried to give the username and password but it just flashed black, loading for awhile then showing the log in screen again. So I could find no way to use my Ubuntu. I tried the console mode, and the console mode ran ok. But is there anyway I can get back to the nice graphic mode or I can do something like "system restore" of Windows? Btw, can I retrieve Linux data from Windows? I have some important files in Linux and just like I said, I can't use Ubuntu right now

type sudo gdm. ANy errors or output?

no error but it just brings me back to the log in screen and the same thing happens: log in screen-> loading -> log in screen again...
The graphic of the log in screen displays perfectly so I thinks it's not the graphic issue. Just the problem that I can't get through the log in screen though I typed the correct password (it just flash black, then loading after typing the password, no message at all)

Some ideas, probably not the best though ^_^:

- Ctrl+Alt+Backspace restarts X. Maybe this changes something.
- Under "Options" (lower-left corner of the screen) choose another session. Try "GNOME Failsafe".
- Have a look at /var/log/messages or /var/log/gdm/*. (If you can't use gedit, install nano to be used from the console.)