一个钩子问题

这几天在看《逆向工程核心原理》时遇到一个问题：
书中的源码如下：
-----------------exe文件----------------------
#include "stdio.h"
#include "conio.h"
#include "windows.h"

#define DEF_DLL_NAME "KeyHook.dll"
#define DEF_HOOKSTART "HookStart"
#define DEF_HOOKSTOP "HookStop"

typedef void (*PFN_HOOKSTART)();
typedef void (*PFN_HOOKSTOP)();

void main()
{
HMODULE hDll = NULL;
PFN_HOOKSTART HookStart = NULL;
PFN_HOOKSTOP HookStop = NULL;
char ch = 0;

// KeyHook.dll 로딩
hDll = LoadLibraryA(DEF_DLL_NAME);
if( hDll == NULL )
{
printf("LoadLibrary(%s) failed!!! [%d]", DEF_DLL_NAME, GetLastError());
return;
}

// export 함수 주소 얻기
HookStart = (PFN_HOOKSTART)GetProcAddress(hDll, DEF_HOOKSTART);
HookStop = (PFN_HOOKSTOP)GetProcAddress(hDll, DEF_HOOKSTOP);

// 후킹 시작
HookStart();

// 사용자가 'q' 를 입력할 때까지 대기
printf("press 'q' to quit!\n");
while( _getch() != 'q' ) ;

// 후킹 종료
HookStop();

// KeyHook.dll 언로딩
FreeLibrary(hDll);
}
--------------------------------

----------------------dll文件-----------------------
#include "stdio.h"
#include "windows.h"

#define DEF_PROCESS_NAME "notepad.exe"

HINSTANCE g_hInstance = NULL;
HHOOK g_hHook = NULL;
HWND g_hWnd = NULL;

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD dwReason, LPVOID lpvReserved)
{
switch( dwReason )
{
case DLL_PROCESS_ATTACH:
g_hInstance = hinstDLL;
break;

case DLL_PROCESS_DETACH:
break;
}

return TRUE;
}

LRESULT CALLBACK KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
char szPath[MAX_PATH] = {0,};
char *p = NULL;

if( nCode >= 0 )
{
// bit 31 : 0 => press, 1 => release
if( !(lParam & 0x80000000) )
{
GetModuleFileNameA(NULL, szPath, MAX_PATH);
p = strrchr(szPath, '\\');

// 현재 프로세스 이름을 비교해서 만약 notepad.exe 라면 0 아닌 값을 리턴함
// => 0 아닌 값을 리턴하면 메시지는 다음으로 전달되지 않음
if( !_stricmp(p + 1, DEF_PROCESS_NAME) )
return 1;
}
}

// 일반적인 경우에는 CallNextHookEx() 를 호출하여
// 응용프로그램 (혹은 다음 훅) 으로 메시지를 전달함
return CallNextHookEx(g_hHook, nCode, wParam, lParam);
}

#ifdef __cplusplus
extern "C" {
#endif
__declspec(dllexport) void HookStart()
{
g_hHook = SetWindowsHookEx(WH_KEYBOARD, KeyboardProc, g_hInstance, 0);
}

__declspec(dllexport) void HookStop()
{
if( g_hHook )
{
UnhookWindowsHookEx(g_hHook);
g_hHook = NULL;
}
}
#ifdef __cplusplus
}
#endif
--------------------------------------------------------------
编译运行后，按书中说道在windowsxp，win7/32位下没问题，

我在机器上运行了后（win7/64），出现了一个个问题
该程序 控制台窗口输入进一个字符就失去响应，其他的程序有的也同样是失去响应，只有少许程序，pdf，qq，notepad没有失去响应，为什么会出现这个样子呢？