Audio command software?

Hi e1!!
I was customizing my laptop when I had a weird idea...
what if I could find a way to "audiocommand" my computer?!?
So I started to look for somekind of software that could let me do that, maybe whit my microfone...
But unfortunatly I couldn't go far with my research..
I reckon this is a futuristic idea that is around since long time, but I never actually thought of having the actual program. It must be out there!!!
Can anyone help me find it?

PS: am running Windows 7

There's an add-on for commanding the browser Opera by voice, it's been around for some time.

But I've never come across something for doing it with the whole computer. Even if it exists, I'd consider it too risky for bugs, side effects and malfunctions caused by environmental sounds. Besides, it would only be practical for a few basic operations, otherwise all those commands would take some learning.

I remember a program called "Dragon NaturallySpeaking", maybe that is what you're looking for?