I have a Lenovo Thinkpad T410 which used to run nice under 11.10. Yesterday I upgraded to 12.04 and from that point on I cannot login. My laptop boots normally and I am presented with the log in screen in which I type my password / or scan my fingerprint and it seems that it is accepted because the screen goes black. After that some output is show for a very brief time and I am again directed back to the log in screen. My password is correct because every time I use a wrong one it does not go to the black screen. I tried removing and reinstalling nvidia current drivers but nothing changes. I am able to enter into guest session but that is not helpful.
I tried the fsck option and the dpkg and failsafe graphics in the recovery mode but nothing helped. I tried all the apt-get clean, -f install, purge, autoremove and every other thing I could imagine. If anyone has an idea I am more than welcome to try.