Subject: How does quantum computing work ?

Well I know other people have asked this question but the answers didn't seem 
to satisfy me. I'm no physicist or computer scientist, but I've studied a bit 
of quantum mechanics a long while back. I understand (atleast superficially) 
that the premise for quantum computing is that ordinary 0 or 1 bits can instead 
be written as a superposition of +1/2 and -1/2 quantum states. What I don't 
understand is how such states can be used to store data if the result could 
change every time you make an observation - or for that matter how one would go 
any sort of computation ? I don't particularly want a rigorous mathematical 
proof of the concept - just a lay explanation of the ideas behind it.

Thanks for your time !

Re: How does quantum computing work ?