Software :: Admin Account Deleted - Guest Password Not Recognized?

I had been trying to install software updates for about a week and each time after I typed in my admin password in the prompt, the prompt kept shaking as if the password was incorrect (which it wasn't because it's the only password I ever use so I know it by heart and the caps lock button was not on). I tried going to my System Preferences page and clicking on the Accounts button. All of the other buttons seemed to work just fine (Appearance, Desktop & Screen Saver, Dock, etc). But my Accounts page took too long to load (it was blank) so I just figured my computer was being slow since it hadn't been shut down in a while. I usually just let my computer fall asleep so that when I use it again, I can just shake the mouse and it would be ready to go. I guess that is what triggered it. I was on the computer last night doing my usual stuff. I didn't download anything funny, didn't try to do any more updates, etc. But my computer was running extra slow so I decided to restart it. When my computer got to the log in screen, my administrator account wasn't showing. I have 2 accounts, the admin and one titled "Guest". It automatically took me to the Guest user log in. But when I entered that password it kept saying the password was incorrect. I know the password and I didn't have caps lock on or anything so there is something wrong with my user accounts and passwords. How do I fix this? More specifically, how do I fix my user accounts and passwords when I can't log into my computer through a standard account and my admin account isn't even showing up?