Computer won't work

[gabzillaplaysmc]

I downloaded a new game off of steam and ran it, but then my computer froze. I shut down the computer and when I turned it back on, it wasn't responding to anything and was frozen at the welcome screen. I shut the power off again a few more times but it still won't work. Is there a way to fix this?

 

[popatim]

<Moved from Windows Vista>