File Search - more in depth help needed

This code, not written by me just edited, scans the given directory for mp3's, problem is it only scans that folder. IE if you type c:\ and c:\ had immeadiate mp3s, not in folders, it'll pick them up. How can i alter this code so that when c:\ is enterd it scans all the subfolders also, ie searches the entire hard disk. Heres the code:

Code:

#include <windows.h>//For FindFirstFile etc
#include <iostream>//For cout etc
#include <string>//For...well...ugh...string!
using std::string;
using std::cout;
using std::cin;
using std::endl;

int main(int argc,char** argv){

	WIN32_FIND_DATA wfd;//This holds the data on a found file
	string str;//To hold directory path
	int i = 0;

	cout << "Enter Directory: ";
	cin>>str;//Get path
	cout<<"\n";

	str += "\\*.mp3*";//Add this to indicate we want mp3 files

	
	HANDLE hFile =  FindFirstFile(str.c_str(),&wfd);//Find first
	if(hFile ==INVALID_HANDLE_VALUE){//If error..abort
	
	
		cout << "Error!! Aborting" << endl;
		return 1;
	}

	do{
		cout << wfd.cFileName << endl;
		i++;
		
	}while(FindNextFile(hFile,&wfd));//Get the rest of the files

	cout<<"\nFound "<<i<<" Files.\n"<<endl;

	FindClose(hFile);//Clean up!
	return 0;

}

Check the dwFileAttributes field in WIN32_FIND_DATA, if the FILE_ATTRIBUTE_DIRECTORY flag is set, then you can enter that directory using cFileName and start searching.

if (wfd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
cout << "Directory named " << wfd.cFileName << " found!";