Debian :: Screen Black After One Move From X To Virtual Console

After upgrading my Debian from Lenny to Squeeze a few things don't work properly. Most disturbing is that after one switch from graphic screen (x, Gnome) to the virtual consoles this can be observed:

1) The virtual consoles show only a small font. It doesn't change when I use 'dpkg-reconfigure console-setup'. Otherwise everything seems to function properly, but then

2) I return to x (with Alt+F7), and if I again want to reach the virtual consoles (with Alt+String+F3, this is a laptop) the screens are persistently black; nothing works, except Alt+F7, which allows me to go back to the x-screen. In this graphic screen it is possible to use the consoles without problem.

3) I have some trouble shutting-down the computer. The screen disappears, everything goes black, but the computer goes on and does not shut down until I press the power-button, forcing the shut-down process. If I press the keys which would bring the computer to a halt through the virtual consoles, I can bring it to stop allthough the screen remains black throughout the whole process. I press: Alt+Strg+F3 to reach the consoles, there 'root + password', Enter, halt, Enter. Nothing at all appears on the screen, but after a while the computer stops.