can't play the minecraft demo please help

[angelfire04]

everytime i try to launch minecraft demo to play it, it then crashes and claims
A fatal error has been detected by the Java Runtime Environment:
EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x061ebf00, pid=4616, tid=5304
JRE version: Java(TM) SE Runtime Environment (7.0_51-b13) (build 1.7.0_51-b13)
Java VM: Java HotSpot(TM) Client VM (24.51-b03 mixed mode, sharing windows-x86 ) Problematic frame: C 0x061ebf00
Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
If you would like to submit a bug report, please visit: http://bugreport.sun.com/bugreport/crash.jsp
The crash happened outside the Java Virtual Machine in native code.
See problematic frame for where to report the bug.

I have tried deleting java and reinstalling both java and minecraft i would love to be able to demo it before i spend the money to buy it and i am out of ideas i have been trying everything i can think of if you could please help i am useing a dell labtop with windows vista to try and run it on

 

[angelfire04]

i have redownloaded java multiple times it works on my friends laptop just fine and she has vista she is the one who is got me wanting to try it before i buy it

 

[angelfire04]

i can't play it on her pc cause we live in diffrent states and what is cracked minecraft and i would love to beable to play the real demo