Cho Chang was a Ravenclaw student at Hogwarts and little Harry Potter's first crush. Before dating Harry, Cho Chang dated Cedric Diggory, but their relationship fell apart when Cedric was savagely murdered by the evil Lord Voldemort and then turned into a vampire. The next year, Cho dated our boy Harry and cried when she first kissed him. Most kids have awkward first kisses, but if you actually leave the girl crying, something has gone horribly wrong. After the crying kiss incident, Harry and Cho actually went on one more date, which somehow went even worse!
After that, Cho Chang quietly retired to a convent probably.