Why does minecraft not work?

Okay, so I JUST got Minecraft and we downloaded it, but every time I click on Multiplayer it just freezes and crashes saying it's not responding. When I go onto single player I have to create a world since I don't have any and when I click "create world" it freezes and crashes AGAIN! Again it's saying it's not responding, I have tried to delete it and re-download it but it hasn't worked, I've tried turning my computer on and off and still not working. I have a Toshiba Windows 8 computer. If anyone can help me please answer, I really want to play this game with my brother and my friends and it won't let me.

Sounds like you need a better computer. Sorry. I'm assuming the specs on your computer aren't good enough to run the game. You're going to have to be more specific than a Toshiba computer, otherwise, I can't help you.

Well your PC might not be strong enough to play minecraft, i.e. It may not have enough RAM to process the game, but i can't be specific since you did not give the specs of your PC

Try Updating Java

This is what is take to run this game on windows 8 computer.
go to http://www.systemrequirementslab.com/cyri?gameName=minecraft&itemId=11356&p=r