HANOI, Vietnam, April 26 — It was Lenin's birthday. The most important Communist Party meeting in five years was under way. And the star of the show was the world's most famous capitalist, Bill Gates. The president, the prime minister and the deputy prime minister all excused themselves from the party meeting on Saturday to have their pictures taken with Mr. Gates, who has more star power in Vietnam than any of them. When people heard he was in town, hundreds climbed trees and pushed through police lines to get a glimpse of him. He was the subject of the...