Go to C:\Documents and Settings\All Users\Application
Data\Microsoft\Crypto\RSA\S-1-5-18 and delete the files in there.
Scheduled Tasks will recreate the files needed.
Note: This folder is hidden by default. Go to Start/Run and type in:
control folders. View: Show hidden files and folders.
Also try running without a password:
For Pro: Start/Control Panel/Administrative Tools/Local Security
Policy/Local Policies/Security options. In the right hand pane (third down).
Accounts: Limit local account use of blank passwords to console logon only.
This is enabled by default, disable it.
For Home: Run Scheduled Task without a Password (Line 67)
Scheduled Tasks - Auto Start (getting tasks to run when no one is
logged on). If you follow these steps, the shedlgu.txt file will be
replaced without any information other than system start-up information upon
the first boot.
Go to Start/Run/Msconfig. Click Selective Startup and uncheck Load System
Services, click ok. Reboot.
Upon reboot, click OK to the first Window that indicates that you have
selected "Selective Startup". When the System Configuration Utility
reappears, Check the Normal Startup Box.
Then go to Start/Search and type in: schedlgu.txt. When it appears, right
click on the file and delete it. Reboot.
You will now have a new Task Scheduler Log File. It can be checked by going
to Start/Search and typing in: schedlgu.txt. Appearing will be your new Task