You can almost feel bad for Megatron. In the movie, you see that hes a shell of his formerself and he knows it. Forced to find an earth vehicle mode, he ends up with a weathered beat up tanker. His base of operations was in a desert in Africa surrended by his hatchlings in cannisters. He is put in his place by Sentinel Prime during the activation of the pillers by getting his head slammed. The most telling of his downfall, when all the decepticons are fighting and Cybertron is nearing orbit, he is lying against a wall looking pathetic until Carly convinces him to take out Sentinel.