Dragon Naturally Speaking

I have been recently using a propriety voice recognition software, and while I know a 'PortableApps' version of propriety software isn't possible, I was wondering can such a program run from a USB hard drive (ie without modification)?

I suppose, like others here, I'm in love with portable 'apping' while others may not be . . . but it seems like a great idea if possible.

Has anyone had experience with this program on an external hard drive?