Then you have some learning to do.
Avoid sprintf(_s). Alternatives for C++ is Boost Format. Either it's vendor lockin (ie, not portable), or it's a security risk.
Instead of C-style strings, use std::string. You can still use the member function c_str() to get a C-style string to pass to Win API.
But even better, scrap Win32 Programming and learn a framework, such as Qt.