That's very much not what quantum computing is about, sorry.

It does not do exponential parallelism by trying many things at once. What it does do is create exponentially many paths, while some of which interfere with one another destructively. When you observe the system, then, some paths will have probability zero even though they have non-zero complex amplitudes associated with it.

Scott Aaronson's "Limits of Quantum Computers" to the rescue: http://www.cs.virginia.edu/~robins/The_Limits_of_Quantum_Com...