Migrating windows 2000/Visual c++ 7 code to windows 7

[hotch]

I have developed a lot of physics code with OpenGL graphics, my own Object Oriented GUI, database code etc. over the years on my Windows 2000 system with MS Visual C++ 7. I have attempted to keep all code completely ANSI so it would run without change across the major operating systems. I am not using anything specific to Microsoft's c++ classes.
Does anyone know how difficult it will be to migrate that code to a current windows 7 machine with the latest version of Visual C++?

[FlashDrive]

I guess, there'd be no problem if you only copy the source code.