On the form that you want to disable right click, try the following...
1) In design view (of the form) select properties.
It should be properties for the Form
2) Select the Other Tab
3) Goto the Shortcut Menu property and change Yes to No
That's it.
Now, when the form is loaded you see that the use cannot right click on the current form.
You must do this to all the forms that you don't want users to right click on.
Hope this helps,
tc3of4