Nanci Ryder, a powerful Hollywood publicist and co-founder of BWR Public Relations who became close to such stars as Rene Zellweger and Courteney Cox, died Thursday of Lou Gehrigs disease in Los Angeles. Zellweger thanked Ryder in her best actress acceptance speech when she won the Academy Award for Judy earlier this year. Stints at Goldberg-Ehrlich Public Relations and Management and Michael Levine Public Relations followed, before she formed Nanci Ryder Public Relations in 1984, with Fox as her first client. In 1987, she co-founded the firm BWR Public Relations with Paul Baker and Larry Winokur. This spring, the firm's parent company, Burson Cohn & Wolfe, shut down BWR Public Relations, moving staffers or laying them off.