windows程序设计上的代码，如下

#include<windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE HPrevInstance,
                   PSTR szCmdLine,int iCmdShow)
{
    static TCHAR szAppName[]=TEXT("HelloWin");
    HWND hwnd;
    MSG msg;
    WNDCLASS wndclass;
    wndclass.style=CS_HREDRAW|CS_VREDRAW;
    wndclass.lpfnWndProc=WndProc;
    wndclass.cbClsExtra=0;
    wndclass.cbWndExtra=0;
    wndclass.hInstance=hInstance;
    wndclass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
    wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);
    wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName=NULL;
    wndclass.lpszClassName=szAppName;

    if(!RegisterClass(&wndclass))
    {
        MessageBox(NULL,TEXT("This program requires Windows NT!"),
            szAppName,MB_ICONERROR);
        return 0;
    }
    hwnd=CreateWindow(szAppName,                  //windows class
                      TEXT("The Hello Program"),  //window caption
                      WS_OVERLAPPEDWINDOW,         //window style
                      CW_USEDEFAULT,              //initial x position
                      CW_USEDEFAULT,              //initial y position
                      CW_USEDEFAULT,              //initial x size
                      CW_USEDEFAULT,              //INITIAL Y SIZE
                      NULL,                       //parent window handle
                      NULL,                       //window menu handle
                      hInstance,                  //program Instance handle
                      NULL);                      //creation parameters

    ShowWindow(hwnd,iCmdShow);
    UpdateWindow(hwnd);

    while(GetMessage(&msg,NULL,0,0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    RECT rect;

    switch(message)
    {
    case WM_CREATE:
        PlaySound(TEXT("hellowin.wav"),NULL,SND_FILENAME|SND_ASYNC);
        return 0;

    case WM_PAINT:
        hdc=BeginPaint(hwnd,&ps);
        GetClientRect(hwnd,&rect);
        DrawText(hdc,TEXT("Hello Windows xp!"),-1,&rect,
            DT_SINGLELINE|DT_CENTER|DT_VCENTER);
        EndPaint(hwnd,&ps);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DelWindowProc(hwnd,message,wParam,lParam);
}

编译没有错误，连接有错误
错误提示如下
--------------------Configuration: HELLOWIN - Win32 Debug--------------------
Linking...
HELLOWIN.OBJ : error LNK2001: unresolved external symbol _DelWindowProc
HELLOWIN.OBJ : error LNK2001: unresolved external symbol __imp__PlaySoundA@12
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/HELLOWIN.exe : fatal error LNK1120: 3 unresolved externals

操作系统是xp，用的是vc++6.0，请问怎么解决

大神啊，来吧