thanks for the info....
... i found out by myself that I could fix this via the safe mode in win 7 & taking ownership of the drives.
then i could reset the permissions to the required users.
Don't know why I even thought of trying safe mode to access the drives.... ...but once there I could at least see the security info and restore the access.
I had to hunt & experiment, but got to the same outcome. Been at it a few days now.
Too bad I hadn't thought to you ask sooner; your step by step info is much clearer.
Maybe a couple of tags around the topic of 'can't access my D Drive' or 'how to restore access to hidden drives' would help others with the same problem with a google search?
again thanks, your solution is bang on.