My Computer is EVIL.

Dang it, why is it that every time I try to fix something myself, it always gets more broken than before? I'm not a retard, I promise. But I did something wrong to my computer and now it won't let me in. Does anyone know how to fix this?

Here's what I did:
-First, I didn't like how every time I turned on the computer it made me enter my password (it's a laptop, so I'm the only one to use it) so I went into User Settings and made it not a password protected account.
-Then, I didn't like how it kept making me click my username to get onto the desktop, because every time the screen saver would come on I would have to click in again. So I just deleted the welcome screen feature, and I deleted this other random account that was called "Machine 2" or something (which I was pretty sure I had not installed).
-But now, however, I can't get my computer to let me on it. Every time I turn it on it says "This computer has been locked by user" and it makes me put in a password. The problem is, NONE OF MY PASSWORDS WILL WORK!!! I can't fathom what the password could possibly be, and so every attempt tells me I can't log in. This upsets me, as I'm pretty sure I brought it upon myself and I cannot see any possible way to bypass the hated screen.

WILL SOMEBODY PLEASE HELP ME??? Ayuda me por favor...