I use terminal services to manage a vista machines on a domain-less lan. After I am done with that session I would like Vista to re-login to the previous account.
How do I pull this off?
Well you don't. I recall a similar question from SO.
But as it's Vista it should always work in fast user switching mode and lock the current user's session while you log on - after you log off, that user can unlock/switch to his session again, right?
Sounds like you need VNC instead of Remote Desktop?
This logs you in as the currently logged on user (think screen-sharing)
Then you can use the "runas" command to get admin for specific operations if you need it.