Adding configuration (by username) to a stack

[Len Morgan]

I have an application that's been out in the "wild" for about 3 years 
now and the customer is asking for some updates.  One of the items that 
they want to change is adding the ability to do certain things like 
delete records (currently they call me and I do this remotely) but they 
only want to have certain people, based on the name they log in with, to 
be able to do it.

I've been toying around with several different methods but I'd really 
like some advice on what might be the best way to make these changes to 
a well established program.  What I'm going to need to do is:

Have certain menu items either disabled or removed based on the user's 
rights.
Have some buttons on various cards either disabled or invisible.
Have certain pop up stacks come up in either read-only or read-write mode.

I would like to have a system of "profile" stacks (this seems the most 
manageable to me), one for each role.  I already validate their login 
from a database and get a profile description (like "Administrator") and 
a profile name (like "admin") for each user but I've never done anything 
with them.

Any suggestions or pointing of the way would be appreciated.

len morgan