A notice appeared that a Kaspersky 2011 update was ready to install. The computer was running Kaspersky 2010.
The download and install seemed to go OK until the reboot was required. The computer comes to the user log in screeen, but the USB ports seem inactive and the mouse and keyboard do not work. The computer does not have PS2 ports.
It does the same in safe mode. The ports work until windows gets part way loaded.