As of this writing, PS3 firmware update 4.45 has been taken down from the site and Sony Computer Entertainment has said publicly that they are currently fixing the problem. Users have been advised not to update their PS3s until further notice.
Problems associated with a new firmware update were so severe that Sony has been forced to take it down and warn PS3 users not to update their consoles for the time being. The trouble with the updates first came to light on this PlayStation support thread, warning users that the "new firmware update may brick your console."
In that thread one user said that after the PS3 logo was displayed after updating, the crossbar menu did not show up. The user tried restarting the console, but the same problem still persisted. Reports on the thread pointed out that PS3s over 500GB were affected by the error. One of the main features of the new update is to allow users to disable trophy notifications during gameplay.