[Sebazz]

- No, any code dont work for delete folder with all extracted files from Program Files when i cancel during instalation.
I tried this and any worked.

Exec(ExpandConstant('{uninstallexe}'),'/verysilent','',SW_HIDE, ewWaitUntilTerminated, ResultCode);

or/and

DelTree(ExpandConstant('{app}'), True, True, True);

- Searching in the web i found this code, but i dont know how implement this in the CancelButtonClick Code or if can work

function deleteDir(): Boolean;
var
ResultCode: Integer;
begin
//allow to delete completely installation folder
Exec('cmd', ExpandConstant('/c RMDIR /S /Q "{app}"'), '', SW_SHOW, ewWaitUntilTerminated, ResultCode);
Result := True;
end;