Corrector Yui

In a world where computers handle everyone's daily needs, the worst has happened: the computers have taken over Humanity's only hope is Yui Kasuga, a not-so-tech-savvy school girl who accidentally discovers a living computer program called I.R. and is transported into a computer-generated world. Together with I.R., she must fight Grosser, the evil master control program.

(Source: Tokyopop)