Hi,
There is a 'Scheduled Tasks' available in most Windows server versions (start -> control panel -> Scheduled Tasks) - you could add it in here.
Beware (as above) it does need to run under a user account but no-one needs to be logged in.
Windows service is still good advice though!
Hope this helps,
Graeme
"Just beacuse you're paranoid, don't mean they're not after you