Lost Safari icon

I seemed to have lost my Safari icon. I think my youngest son tried to download a new safari that wasn't compatible with my mac. I tried everything i know of to get it back. I can't even log on to the internet because i can't even seem to locate the browser. Any idea's on what to do. I even download safari from Apple on my disk drive. My system told me i can't download safari on this computer?? I'm lost big time!