I am hearing voices/noises from inside my computer?

No I am not insane and no i'm not ogn drugs. I just bought a older computer on craigslist earlier today and a little bit ago I started hearing noises coming from inside. I mean ******* distinct noises. One was a whimpering dog which I am a hundred percent on. And another was a woman talking, making a statement of some kind. and then I heard a man cough three times. What the **** is going on here. I swear this is fecking insanely freaking me out. can wireless cards pick up radio/phone frequencies. Please and thanks.