I recently realized that my Norton system scan wasn't running
even though it was properly set up in the task scheduler. Turns
it had to do with blank passwords for Windows logons.
With some Google Group searching I found this useful info :
Those of you having a problem with the scheduler might want to
check this out. Worked for me. I did notice that if the task
already exists you have to add it then delete it before the change takes effect.
The relevant section states :
Scheduled Tasks - Applying/Running tasks without a password
For Pro: Go to Start/Administrative Tools/'Local Security
Policy/Security Settings\Local Policies\Security Options
Accounts: Limit local account use of blank passwords to console logon only. This is enabled by default, disable it.
For Home: (Keith Miller) Go to Start/Run/Regedit and navigate to this key:
Value name: limitblankpassworduse, Type: REG_DWORD, Data: 0 (disabled) 1 (enabled)
For Home: Run Scheduled Task without a Password (Line 67)