No. You cannot convert an already-compiled program.
As Bill said, if you have the source code (and I think you do) then you can use a newer compiler to compile for the newer systems.
As many have suggested to your many other questions, Visual Studio Express may be the right tool to use.
Another option is to simply use a newer, but still rather old, compiler. This link
Borland C++ Compiler version 5.5[
^] will get you the Borland C/C++ 5.5 compiler and linker and a few other tools --
Borland C++ 5.5 for Win32 Copyright (c) 1993, 2000 Borland
-- this is essentially what Turbo C grew up to be (but with no IDE). Once you use Turbo C to write and debug your program you could then compile it with this newer compiler. I use this compiler for some things I write and I have confirmed that an EXE created with it will execute on Win 8.1 64-bit.
You could also choose to use the C/C++ compiler available from MinGW; I use that one too some times, though usually only the pre-processor.
Quincy[
^] may also be an option. It's a simple Windows C/C++ IDE -- I haven't really used it, but it's worth a look if you like simple tools as much as I do.
Your best course of action is still to use a modern IDE and compiler.