//加上 Windows单元

var hAppMutex: THandle; begin   Application.Initialize;   hAppMutex := CreateMutex(nil, false,'PaiWeiControl'); if (hAppMutex = 0) then begin     MessageBox(0,'创建互斥对象失败!','Error',MB_OK + MB_ICONINFORMATION );     Exit; end; if ((hAppMutex <> 0) and (GetLastError() = ERROR_ALREADY_EXISTS)) then begin     MessageBox(0,'只能运行一个相同程序!','Error',MB_OK + MB_ICONINFORMATION );     CloseHandle(hAppMutex);     Exit; end;   Application.CreateForm(Tlogout, logout);   Application.Run;   CloseHandle(hAppMutex); end.