Has anyone found a way within .Net to delete an object from memory explicity?

I'm writing an application that needs to delete object A whether or not other objects still have a reference to it, and it needs to delete them when I tell it to.

If not, then here's a couple of questions.

What happens in C++ if you do the above? Object B's reference to Object A now points to null? For the lifetime of Object B?

What would happen if I wrote a simple function in C++ to delete objects and had my C# code call it as an extern? Would the GC flip out?

This is driving me crazy as I move on to some pretty advanced stuff with the app, and still can't find a way to delete an object. Any help is greatly appreciated.

Thanks
Yagi