Make sure and compile the program after you make changes. If it still doesn't work, try doing "Rebuild All" (this will compile the entire program, even parts it thinks don't need compiling).
If it STILL doesn't work, then you'll need to specify what "output window" you're talking about, and maybe give a few more specifics about what your program is trying to do, and what isn't working.
EDIT:
Well that's very strange. Are you sure it is compiling without errors? If not, then it didn't compile, and you'll still be running the old version of the executable.
How are you running the program after you compile it? Are you doing F5 from within Visual Studio, or are you running the exe separately from outside VS? Try it both ways. If it won't work, check the "modified" date of the exe file outside VS, and see if it's actually getting changed when you recompile the program.
If you STILL can't get it to work, put some more "debugging output" in your programe. Like, put cout << "test1" right before you call user(), and cout << "test2" right after, and see if the "test 1" and "test 2" show in your output. If you do see them, then the problem is something else.
Could it be that it doesn't like the fact that you have a function called "user()" as well as a "Users" class also called "user"? It wouldn't hurt to rename one of those to something else, for instance rename "void user()" to "void PromptUser()"