If the program is service, you can find with IsServiceRunning API. If it is Window/Dialog Exe, you can do it with FindWindowEx API. Read how to use FindWindowEx API.

Product architect needs to be through knowledge of the product,it's future enhancements, applicability, customer's views/needs, compititors and there drawbacks, product design and technologies used, so on.... There are no books for becoming Product architecture, you need to be working on that product and need to gain knowledge about it...

Use atoi API

Run the Microsoft Tools->Dependency walker and put the dll in it. It will show all dependency.

This is not possible. Instead you can have MDI and achive the required functionality.

TCHAR is windows datatype, it will get converted to char or wchar depending on #define BSTR is COM data type and is unicode compliant, it will always use the string in unicode format. _bstr_t is also com data type and it encapsulates the BSTR data type. _variant_t is VARIANT data type and can accept contain any datatype defined in union it has. Atul

can #pragma comment(lib, "libname.lib") help??

I have written a dll and exported classes. I don't want to give header file to clients. How this can be done. I want only to give lib file and dll to the user.

But in COM you can't derive a coclass from another coclass.