Did Joseph Stalin rise to power by assassinating Lenin?

No, because Lenin died of natural causes in 1924 after suffering a stroke in 1922. After Lenin died there was uncertainty as to who would lead the country. The four main people involved were Leon Trotsky, Grigory Zinoviev, Nikolai Bukharin and Joseph Stalin. Stalin allied himself with Zinoviev and ousted Trotsky. Then he allied himself with Bukharin and ousted Zinoviev. By this time Bukharin realized he had been duped by Stalin and that he, Bukharin had no power base. Stalin was able to seize control of Central Committee and have full power to rule.