Since I added a network drive to a windows 7 system, I get a black screen with mouse movable around whenever I login while the network cable is disconnected.
After a full disk format and windows re-installation I got back to this situation but this time I discovered this problem was caused by the National Instruments VISA (NI-VISA) engine as it appeared just after installing it. It should be noted that at the point of installing NI-VISA engine, the network drive was already setup but it was making no problem at all. Also, when I got this problem the first time, the NI-VISA engine was already installed since long.
Booting windows in failsafe mode results with the same problem unless I choose the failsafe without networking enabled mode.