Even two big jackpot winners on Who Wants to Be a Millionaire could not ignite ABC for the week ending April 15, with CBS's "Must-Now-See" Thursday keeping the network on top with an average of 12.37 million viewers — 2.53 million more than ABC. Of the Big Three, NBC remained the weakest link, with 2.33 million less viewers than this week last year. Although consistency was the word at Fox, weblets UPN and the WB both dipped from year-ago viewing levels. The top five shows of the week were: Survivor: The Australian Outback, CSI: Crime Scene Investigation, Millionaire, CSI (repeat) and Everybody Loves Raymond.