What happened when i was playing terraria??? PLEASE HELP?

I was playing Terraria on my laptop, i have an hp dv6-6167cl entertainment laptop if you were wondering, and my computer went into a shutdown mode saying that it was shutting down to protect my computer from any harm. I think the reason why is because i downloaded something and it didnt download right. The only things i have downloaded are Steam, Terraria, itunes, skype, and mozilla firefox. Please help because i want to play Terraria on my laptop but i also dont want to screw my laptop up