I'll also endorse mingw: [
mingw.org] . A little bit complicated to install, however...
If you want something more easily installed, WxDevC++ is an IDE that uses the mingw compiler, all in an install file: [
wxdsgn.sourceforge.net] . It's not maintained, but I use it as-is to develop Windows applications with no problems.
Visual Studio has a free version, but it takes up a ginormous amount of disk space.
And then, someone pointed out that the Borland compiler can be had for free. There's nothing like picking up where you left off, in the same programming environment... [
www.embarcadero.com]