>Hi,
>1. How to set access level to NOT allow use to launch a particualr form?

Create a iControlID & description for the form. Then in the security, set that particular item access to "None" for a given user and/or user group. You might want to do the same for any menu item that launches the form.

>2. Why user/user group form always able to be accessd by any user? How to set it to only accessible by administrator?
>

Just assign it a iControlID like any other form, or restrict access to the menu item that launches it. If you modify the CUserGroups form to do this, I'd suggest subclassing it and modify the Classes.DBF to point to your subclass