I dealt with a weird incident at work involving a lady who thought she'd got a virus, the machine was typing random words in a document by itself. She'd inadvertently started the built in MS dictation and somehow minimised it so the only sign of it was a tiny thin toolbar at the top edge of the screen - by thin I mean about 5 pixels deep. The built-in mic on her laptop then attempted to translate her words. Without much success!
One thing with Dragon is you do need a good quality headset/microphone and sound card for it to work really well. It has inbuilt diagnostics as well though.