C++ Compiler 5.5
That'll get you the good old fashioned Borland C++ compiler. I haven't used it in ages, so I don't know what it's like now, but it's a much smaller download than MS Visual C, and it sounds like you just want to do this one project.
E: Took a look, all the old standards are still there. The command is "make." Just put that Borland stuff in a folder with a nice short path like c:\bcc55(this will save having to set environment variables you're only going to use once), then open a command prompt, change to the directory your nelly2pcm stuff is in, and type c:\bcc55\bin\make nelly2pcm
That should do it.