I use NAV2009R2 Classic Client. I'm not sure, but I think it can be possible to have different menu for each user.
If this is possible, I will appreciate any help.
You can open Navigation Pane Designer (from toolbar). For each module, you can press right mouse click and open 'Assign Users'.
When you open this form, you can easy assign or unassign each user for each module.
If you want to hide complete module from all users, you need to choose 'Hide' command with right click on modul in menu (without Navigation Pane Designer).