A Microsoft security fix has inadvertently left some Windows PCs almost inoperable, app developer Prevx warned this weekend. Those running some security apps after applying a November 10th fix have reported the system starting up with a black screen, nicknamed the "black screen of death," that shows only a single Explorer window. It doesn't prevent complete use of the system but bars use of the Start menu and other features on Windows XP, Vista and 7 systems.
