Programming Forums - How to "ShowModal"

Hello! I am new on C++ and today I have a very big problem. I created a 2 forms (later will be more) program. In the first form I have a button that does this:

Form2->ShowModal();

. But on Form2, after I put this code:

Form2->Close();

i get the following error when I try to open my program: "EAccessViolation" and my program doesn't start.
I think it is because of my

Form2->Close();

code, because when I comment this code, my program works very well. So. How to correctly "ShowModal" a form, then deinitialize it correctly?

Programming environment: Borland CBuilder 6(Trial Version)