Izmeni .dpr fajl ovako:
Code (delphi):
program Project1;
uses
Forms,
Windows,
Unit1 in 'Unit1.pas' {Form1};
{$R *.res}
begin
CreateMutex(nil, False, 'Project1'); //moguca samo jedna instanca
if GetLastError = ERROR_ALREADY_EXISTS then //aplikacije
Halt;
Application.Initialize;
Application.CreateForm(TForm1, Form1);
Application.Run;
end.