I guess you are talking about a constant on heap. If you put a hardware BP on the address and nothing reads (accesses) it then it is not used and probably you got the wrong address. I use ollydbg debugger, it has a "find references" option (ctrl+r), it can find pointers on heap/stack and references in code to the address. (it can't find dynamic references though like mov ebx,dword ptr ds:[eax+8], so you should use (hw) bp if you are unsure)