Hi,
You could try this first:
Add a scheduled task which is triggered at COMPUTER STARTUP and ON DISCONNECT FROM USER SESSION.
If this doesn't resolve your problem, well, you can't do everything more... you need a BACKGROUND process or a SERVICE, but both must be written (so, who has made this program must do something).
There are also 2 others ways:
The first one is taken from msdn:
Ref: http://social.technet.microsoft.com/Forums/en-US/winserverMigration/thread/98a97aee-c62b-4683-94ab-3777899cf7de/
The second one (non-free):
http://www.firedaemon.com/
I never tried the first solution, but if you try it, please report if successful.
Cheers