I attmpted by removing both, but was still able to browse through all the threads.

I appreciate the help though, just didnt work :(

You also have to set forum permissions to guests and users if you didn't set them yet

I cannot see a simple secure solution to your inquiry. You can produce the look and feel of what you are looking for -- if faking it is okay, but establishing a secure method will take a bit of work. Changing the permissions of one module here does affect other modules and most likely other modifications that you are already using. You would need to be able to alter the code as these problems arise.

Assessment under current vBulletin
----------------------------------
1.) Doable - It would be possible to hide the forum so that it is not viewable. Reading of the thread or post is possible, there is no issue. Security could only be established by an obfuscated link. (You would be on your own for the obfuscated link.)

2.) Advanced - Having a guest write to a thread or a post is a security issue and precautions must be taken. A new permission would have to be established and triggered from the obfuscated pushed link. (If I understand your request correctly.)

3.) Advanced - Unless an additional thread permission is added, it would not be possible to secure it from prying eyes. This might affect the performance of your board. Several modules would have to be altered to accomplish this.

If option (1) is all you need, then I think we can give you a rough start. If you think you have the capability to handle the other options, layout what you are thinking in psuedo-code and we will try to fill in the blanks for you, as I have already given this subject some thought.

PS: Showing your project code will always yield you more qualified assistance. :)

Take Care :)