Cannot login in Debian after switching to wheeze
 

I am using Debian and I have recently tried to use the testing (wheezy) package. After I upgraded gcc, gdm3 was removed (I don't know why), but it was possible to install it again using I did so, but now after startup I can see a login screen with a list of users. when I choose a username and type a password, I only see the desktop background and nothing on it. I also run an ssh server, and ssh -X works, but it is too slow.

It may be more complicated than that, but it looks a little bit as if the default session type is something that is not fully configured, like just metacity, compiz (unlikely on debian I guess) or something.

On the login screen there might be some menu where you chose the session type, on some bottom corner usually. Have you tried picking something on that menu before login? I think that preferably something with "session" in its name, more likely "gnome session" unless you've installed something else.

I don't have any "session" string there. There are only "System default" and "TWM"

Finally,
resolved the problem.