Comment 5 for bug 808479

I ran sudo apt-get update and sudo apt-get dist-upgrade from the command line, but when I rebooted to complete updates, I got the logon screen asking me to log on, but the laptop is like freezed, I cannot log on or do anything else, on the top right corner of the screen instead of icons I've go two white rectangles with a red cross in them.

When I saw this the first time, I re-installed the iso again (formatted the HD partition and installed it clean), when I saw that the zeitgeist message appeared again I reopened the command line and re-entered the two commands: sudo apt-get update and sudo apt-get dist-upgrade, rebooted to complete updates, but the same problem occured:

I've got the logon screen asking me to logon, but I can't do anything.
I have to switch off the laptop by pressing the power button.