I had this similar issue just couple of days ago. Suddenly the action/security center reports that antivirus is turned off/not up to date (something along those lines) and then i get an "x" mark on avast (avast antivirus turned off). I then i click control panel but it won't let me go into control panel and suddenly it gives me this dialog message (can't remember what it said, if next time happens i will take a picture via my mobile phone and post it). After it gives me the dialog message. Windows automatically restarts.
After restart everything goes back to normal.