Free will?

[JuliaL]

In the computer example you wouldn't generate a different output if you reset the universe, because of the way the random number is generated (it isn't random). However I'm not sure that with Quantum Mechanics that the same is true. I should have qualified that in my example the random number generator was a perfect one, rather than a real one.

I am not a quantum mechanic nor do I play one on television.
OTOH, your quest for a 'perfect' random number generator is likely futile as you could not know when you found it. Quantum Mechanics apparent randomness has this problem as it may not be random in a way we cannot (currently and maybe forever) measure. Think for a moment of a room of constant temperature, still air. Sweep a detector plane through this and note every point on that plane onto which a molecule of that gas impinges. You'd get an apparently random result though with better knowledge of the micro-mechanics of the gas kinetics that outcome would be predictable (nod here to Heisenberg.) See hidden variable theories: https://en.wikipedia.org/wiki/Hidden_variable_theory
Unfortunately you can't know what the hidden variables are because they're hidden (or non-existant) unknown unknowns.

Is free will just the ability to do something different, or does it imply some sort of choice in this?

I think the word 'will' actually does imply some sort of choice here.