Here's what I did:
1) Went to "Control Panel\User Accounts" and set a user name (eg.
'Jack2003') and a password for the 'Owner' account. The system now refers to
this user as 'Jack2003\Owner'.
2) Clicked 'Start\run'. Entered 'control userpasswords2'. Up popped a
dialog box. Unchecked the box labeled "Users must enter a user name and
password to use this computer". Entered the user name 'Jack2003\Owner' and
the above password in the appropriate places. Clicked "Apply" and "OK".
3) Went to "Control Panel\Scheduled Tasks" to set the scheduled tasks using
the above user name and password.
It works!!!!!!!!!! The scheduled tasks run on schedule unattended and you
don't have to log on to use your computer!!! That is to say, the logon
happens automatically when you reboot or come out of standby. Amazing!!!!
The link to the MS page that tells you how to do step 2) is:
http://support.microsoft.com/default.aspx?scid=kb;en-us;315231
I found it by going to the page given in one of the other replies.