Question on an ISO file

[smh]

I have looked at wiki, documentation, and searched form but I guess this is such a basic question that I cannot find the answer.

I have one file with an iso extension. If I burn itto a dvd disk I can play them. But I cannot open it in VLC media player directly on the pc without having burned it do a dvd. I did not see any category in the help relation direction to files with iso extensions.

Is it just that these files cannot be played directly? Or is there something I need to do that I could not find.

Thanks for any help.