do it through query analyser using sp_droplogin store procedure. that will leave user in the database but the login will be removed so that ID will have no access to SQL server and will not be able to access any databases, so not sure why you want to do this.
PS - I'd rather you did not scan my computer for software I am running.
edit: you cannot remove a login whilst still maintaining access to a database - this request does not make sense.
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