gklundt (12/1/2010)
You cannot disable windows groups.From BOL (TSQL Reference on ALTER LOGIN):
You cannot use ALTER_LOGIN with the DISABLE argument to deny access to a Windows group. For example, ALTER_LOGIN [domain\group] DISABLE will return the following error message:
"Msg 15151, Level 16, State 1, Line 1
"Cannot alter the login 'Domain\Group', because it does not exist or you do not have permission."
This is by design.