One day I started up my computer, and to my surprise neither one of my two printers worked. When I go to control panel and click on printers, no printers are installed. It won't let me add a printer either. It say'd, "Operations could not be completed." I have a HP Deskjet 722C and a Canon S520. Niether one works, but they are both connected, because the power turns on, and they both will spool on startup. I also checked to make sure that they were connected into the computer. One connects into the USB, and the other somewhere else, so it obviously isn't that the USB ports failed or anything because neither work.