My machine used to automatically log me in. It crashed a couple of weeks ago and now it boots to the login screen. when I type in the password, the screen goes black for a couple of seconds and returns to the login screen. Over and over! If I type in an incorrect password, a red error message appears, so I reckon my password is OK. It will let me log in as a guest (no password), but of course I can't access my folders or files as a guest. Ctrl+Alt+F1 sends it into sleep mode!