can't restore data\ folder

Greetings,
I'm running Postgres 8.1.3 on Windows. Last week I made a copy of my data\
folder and then did a bunch of destructive stuff to my database. Now I'm
trying to restore my data\ folder and it is not working:

1. stop postgres
2. copy saved data\ folder into C:\Program Files\Postgres\8.1\data
3. start postgres

The service starts and then stops immediately with no log files. I get a
message from Windows that the service has stopped.

I've tried uninstalling postgres and re-installing it. It still doesn't
work.
I've tried changing all the permissions in the data\ folder, no luck.

I have noticed in the event log that I'm getting this message for the
postgres user:

Windows cannot log you on because your profile cannot be loaded.
Check that you are connected to the network, or that your network is
functioning correctly. If this problem persists, contact your network
administrator.

DETAIL - The system cannot find the file specified

Looking through my event history, it appears I've been getting this same
error for a long time.

I tried removing the postgres user then re-installing postgres to let it
recreate the user. It did,
but I'm still getting the "Windows cannot log you on..." error.

Any help would be appreciated.

-Sam
sbq (at) cayuse (dot) com