What episode was William free from xana?

William was freed from XANA in the episode titled "Final Round," which is the 24th episode of the second season of "Code Lyoko." In this episode, the group successfully defeats XANA and manages to retrieve William from his brainwashing, allowing him to rejoin his friends at Kadic Academy. This moment marks a significant turning point for both William and the group as they continue their battle against XANA.