Mono Gokoro, Mono Musume.

Similar to the protagonist of Henshin!, Hiroaki gains the power of transformation. But unlike Sakagami's power to transform himself into anything, Hiroaki can transform anything into a girl!
He gains this power by opening a strange attachment in his computer. Which suddenly turns his computer into a girl. She tells him that anything he 'Personify' will become his willing servant as well...