Not Reading ISO

[alsoslick]

I downloaded a game from my friend in the ISO format. When I open it alone, it says "Cannot open file: it appears to be a invalid format image!" Then I extracted the files with WinISO and when I click on the extracted version, I get the same message. When I right click on the file i extracted with WinISO and click extract to... it says "No archives found"
If anyone has any idea on what i can do please tell me. It would help a lot. Thanks.