You will need to boot into Safe Mode on your machine and run a tool in the Examsoft folder to restore your settings. Please follow the directions at the following link(s): 


Windows 7

http://support.examsoft.com/link/portal/15157/15194/Article/632/How-do-I-resolve-a-black-screen-missing-task-manager-or-missing-power-option-Windows-Vista-7


Windows 8 & 10

http://support.examsoft.com/link/portal/15157/15194/Article/633/How-do-I-resolve-a-black-screen-missing-task-manager-or-missing-power-option-Windows-8-10