Frees the loaded dynamic-link library (DLL) module and, if necessary,
decrements its reference count. When the reference count reaches zero,
the module is unloaded from the address space of the calling process and
the handle is no longer valid.
BOOL FreeLibrary( HMODULE hModule )
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero.