I've had an issue since last night where my welcome screen is just blank and blue, and when I log in I cannot open up my start screen in any manner (logs right in to desktop). The windows key on the keyboard nor the one on the taskbar open the menu. I am also unable to open some windows, such as PC settings, which when clicked give an explorer.exe class not registered error. I did an SFC scan which gave me the CBS log error and I'm just lost as to what to do now as I cannot find anything around online that helps.