MY LAPTOP WON'T ACCEPT MAC OS X SNOW LEOPARD?

I want to play TF2 on my macbook. It took a good 9 hours to download, then it took a good amount of time "Validating Steam Files." Once it was finally done, I tried to launch TF2, but it said my laptop didn't meet the minimum requirements. So I got the Mac OS X Snow Leopard disc-- which, by the way is the family pack that can go on 5 computers-- and put it in my laptop, but it just made a bunch of whirring noises for a while before eventually spitting it back out. I thought maybe it was upside-down, so i flipped it, and my laptop just spit it out even quicker. Can anyone tell me why it won't work?