help with opening an unzipped file

I d/l ed a file and I launched it from my library it unzipped and I found it in my mac hd I tried playing it but couldnt get it to work. every thing I press will say application not found to open file. What is wrong? Do I need to d/l something to make it work did I do something wrong?

I have osx

thanks

I have been having the same problem. I don't know if the version i downloaded was pc formatted or not. If anybody out there knows what is going on i would be greatly appreciatvie.
mac 4 life