More seriously, most Windows setups will include a "Guest" username. A Guest user may not display on the login page; but the system sometimes defaults to "Guest" if there's an error in selecting the user you want, or in entering the password. (Especially for an error in the password, a machine with a Guest username - displayed or not - may go directly to the Guest desktop rather than waiting for you to re-enter the password.) On most machines, there's little defined for the Guest desktop, so it looks like your machine has been blasted.

If you have shared files, and allow access by "Everybody" the OS assumes that anyone not "legally logged on" is an anonymous "Guest," even if no Guest username has been defined.

The only reasonably certian cure I've found is two cups of coffee before booting up, to make sure the operator is on line before trying to start things.

John