[Setup]
AppName=My Program
AppVersion=1.5
DefaultDirName={pf}\My Program
OutputDir=userdocs:Inno Setup Examples Output

[Code]
function GetWindowsUpdateCount: Integer;
var
  SearchResult: Variant;
  UpdateSession: Variant;
  UpdateSearcher: Variant;
begin
  UpdateSession := CreateOleObject('Microsoft.Update.Session');
  UpdateSession.ClientApplicationID := 'My Inno Setup Installer';
  UpdateSearcher := UpdateSession.CreateUpdateSearcher;
  SearchResult := UpdateSearcher.Search('IsInstalled=0 and Type=''Software'' and IsHidden=0');
  Result := SearchResult.Updates.Count;
end;

procedure InitializeWizard;
var
  UpdateCount: Integer;
begin
  UpdateCount := GetWindowsUpdateCount;
  MsgBox(IntToStr(UpdateCount), mbInformation, MB_OK);
end;