The simplest way? Just use system().
Code:
#include <stdlib.h>
system("something.exe");
Whatever you pass to system() is executed just as if you'd typed it on the command line. Oh, and be sure to include stdlib.h if you want to use system().
For more information, see this FAQ. http://faq.cprogramming.com/cgi-bin/...&id=1043284392
[edit] Any particular reason you're using DJGPP? It's pretty good, but in my opinion Dev-C++ is better, and Code::Blocks better yet (if you have a good enough computer). [/edit]