Open-source alternative for Visual Studio and MFC?

Several years ago I started a small project for a Windows utility. (At this moment I prefer to no disclose too many details on the project.) I used MS Visual C/C++ 6.0; the utility was intended for Windows 95.

The utility basically worked but needed some more fine-tuning (possibly including localisation). I lost the executable (but still have the source!), so I cannot quickly check whether or not it works on Windows XP as well. I never installed VC on XP so far.

As VC 6.0 is now pretty "old ", I would prefer to use a more recent version. But I do not expect to have enough projects for a new VC version to be worth the high expenses.

Could anyone advise me on an appropriate open-source alternative that does run om WIndows XP and is able to compile executables for Windows XP? One way or another I will also need something like Microsoft Foundation Classes for defining Windows controles and the like. The utility must interact with the registry and even (though not much) with SDK (if I remember the name correctly) and the Windows task list. Is there an Open-Source alternative for this, too?

Any good advice is welcome!