If you get the error:
Logon failure: the user has not been granted the requested logon type at this computer
When trying to add a computer to a domain or trying to map a network drive, then chances are someone has been stupid.
Check rsop to make sure that the following policy hasn’t been changed to anything silly:
> Local Security Settings
>> Local Policies
>>> User Rights Assignment
>>>> Access this computer from the network
This should probably be the list that is suggested in the explanation for this policy and at least include Authenticated Users.