This was true in the past, but today almost all major
nations follow the Berne copyright convention. For example,
in the USA, almost everything created privately and originally after April 1,
1989 is copyrighted and protected whether it has a notice or not.
The default you should assume for other people's works is that
they are copyrighted and may not be copied unless you know
otherwise. There are some old works that lost protection
without notice, but frankly you should not risk it unless
you know for sure.
Oh my god..learn some grammar!!