BLOEMFONTEIN - South African President Jacob Zuma, fresh from a landslide re-election as head of the ruling ANC, on Thursday promised to crack down on corruption and feuding that has shaken confidence in the party's leadership of Africa's top economy.In a speech to close a week-long ANC elective conference, Zuma called on the 100-year-old African National Congress to "root out" faction-fighting and the use of money to buy members or influence within the party."The primary task of the ANC going forward is to work for unity," said Zuma, whose re-election this week ended months of feverish speculation over a challenge from Deputy President Kgalema Motlanthe."It is clear that the ANC is renewing itself already," a smiling Zuma told the packed audience.