I used to pay for STO, but now I can't afford it. I would like to play the demo, but when I log in with my user and pass, it just says I cant log in. Of course, its because I no longer pay, but how do I make my account free?
You can't. I'm guessing you're a bit confused with CO being free to play, but STO isn't free (yet?) so if you aren't paying a subscription, you can't play the game and there's no way to revert your account to a demo one.