NEED TO REMOVE "Edit" LINK FROM A PAGE

I have used the "node_access module" for specific modes.this is because i want these nodes to b accessed by only authenticated users that i have created.But after enabling this module i am unable to deny edit and delete permissions for authenticated users.i do it for anonymous users.there are check boxes for permissions for each node.i check the deny edit and delete for authenticated users nad click on save permissions.it shows changes saved but again these boxes automatically become unchecked and permissions are not set thus allowing authenticated users to edit the content.i dont want these.

please help.immediate help will be really appreciated .i am doing it as a third year project which i need to submit this week.so please try and help me quickly.
thank you in advance.