At the office we have a Windows 7 which was configured by a bad admin : he mapped the shares with an administrator user.
This Windows 7 is in a domain, and the admin user is named admin. So this Windows 7 accessed the servers with full rights.
On the Windows 7 I disconnected the drives, rebooted and reconnected them. Everything was running fine.
Later, I disabled the user admin on Active Directory to be sure nobody else used it.
And tadaaa... the former Windows 7 can no longer access the server.
Ok, I re-disconnect the shares, reboot and it is now impossible to reconnect them. I tested with net use but I get an error too.
If I enable admin account this is ok. So I guess the Windows 7 use some credential mapping. It memorize something, but where ?
look in Dredential Manager in Control Panel on the Windows 7 computer and delete the credentials if you find them there.
Run net use from a command prompt and make sure the mapped drives are no longer connected.
What error do you get when you try to reconnect the mapped drives?