Comment 14 for bug 555571

The same happened to me, and I found in http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=566891 people with the same case:
"I restarted my laptop because it could not be resumed: only a black screen with the shell cursor is shown on the top left."
"Network-manager-kde systray says that "network management disabled""
"This fixed my problem:
    service network-manager stop
    rm /var/lib/NetworkManager/NetworkManager.state
    service network-manager start
"