procedure TFORM.FormCreate(Sender: TObject);
var
errno:integer;
hmutex:hwnd;
begin
hmutex:=createmutex(nil,false,pchar(application.Title));
errno:=getlasterror;
if errno=error_already_exists then
begin
ShowMessage('程序已经在运行了');
Application.Terminate;
end;
//....这是你原来的代码继续下去