Xubuntu won't load to desktop, prompting me to log in

I created a live USB for Xubuntu Precise Pangolin, and for the first two days it worked fine, the system would load up, I'd close the install screen and the desktop would load up with all my settings saved and website passwords remembered. On day 3, today, I turned on my computer and xubuntu ran through the normal loading process, including the install screen, but when I closed that, it would prompt me to log in. I have not set a password for my computer, and I can find no information online about how to resolve this problem.

I'm having to use live mode which has become a big inconvenience to me.

I do not have any technical knowledge whatsoever, so please explain any steps I have to take in simple terms.