[Code]
function InitializeSetup: Boolean;
var path: String;
begin
  if RegValueExists(HKEY_LOCAL_MACHINE,'Software\Microsoft\Windows\CurrentVersion\Uninstall\{#MyAppId}_is1', 'QuietUninstallString') then
    begin
      RegQueryStringValue(HKEY_LOCAL_MACHINE,'Software\Microsoft\Windows\CurrentVersion\Uninstall\{#MyAppId}_is1', 'QuietUninstallString', path);
      MsgBox(ExpandConstant(path), mbInformation, MB_OK);
      Result := True;
    end
  else
    begin
      Result := True;
    end
end;