获取当前系统版本（2）

 DWORD dwBufSize = MAX_PATH;
 //get value for product name
 UCHAR szAppPath[MAX_PATH] = {0};
 if (ERROR_SUCCESS != RegQueryValueEx(hKey, SYSTEM_CURRENT_VER_VAR, NULL, NULL,
  szAppPath, &dwBufSize))
 {
  RegCloseKey(hKey);
        return FALSE;
 }
 //if value is 5.0, system is window 2000
 if ('5' == szAppPath[0] && '0' == szAppPath[2])
 {
  version = WINDOWS_SYSTEM_VER_2000;
 }
 //if value is 5.1, system is window xp
 else if ('5' == szAppPath[0] && '1' == szAppPath[2])
 {
  version = WINDOWS_SYSTEM_VER_XP;
 }