Xubuntu hangs on boot

[u3000]

Since the last update (last week), Xubuntu does no longer boot properly.

- Grub loads, choice for xubuntu
- Shows the white mouse
- Gives some messages, but too fast to read
- Shows the loading screen of the login (blue whit moving white dots)
- Gives some more messages (again, too fast to read)
- Blank screen

This is the same with previous kernels in the grub-loader.

Can someone give me some idea to find out what the errors are about?! Or a solution...

Thanks!