I assume your question is not meant to suggest that we have had zombie presidents and you mean "no living formerpresidents".
If I've calculated correctly, the people who have been President of the US at a time when no former president was still alive are George Washington (for obvious reasons), John Adams, Ulysses S. Grant, Theodore Roosevelt, Herbert Hoover (briefly... Coolidge died in January 1933 and Hoover's term expired in March 1933; however, he wasn't quite as alone as the others, since there was already a president-elect by the time of Coolidge's death), and Richard Nixon.
Those are in order, so the short answer is: Richard M. Nixon.
Nicolas Sarkozy was the President before Francois Hollande.
There have been many Vice-Presidents who opted not to run for President. The most recent was Dick Cheney.
Yes. If a president dies or resigns before the end of his current term in office, the vice president automatically becomes president. Of course, the people will have voted for the president and vice president at the most recent presidential election.
In recent years, the President has been more instrumental in choosing the vice-president. In most cases, he picks someone he can work with and whom he trusts. Therefore, he is williing to assign him important missions. Also, the workload on the President has increased - he has more need to have someone he trusts to perform some the duties that Presidents used to do themselves.
The five most recent Presidents before Obama were George W. Bush, Bill Clinton, George H. W. Bush, Ronald Reagan and Jimmy Carter.
Obama,Bush,and Clinton
More US presidents were lawyers before they became President. 25 of the 43 presidents were admitted to the bar, although not all them earned their living that way.Of course, if you consider politician to be a profession, even more of them engaged in that.
Bush and Obama
Barack Obama is the current president. George W. Bush is the most recent president
None of the modern Democratic Presidents have been generals. Before the Civil War, Franklin Pierce is the most recent President who was a general and a member of the old Jacksonian Democratic Party.
Most of the presidents died while not living in Washington. The only presidents who died in Washington while in office were W. H. Harrison,Taylor and Lincoln. Ex-presidents Taft and Wilson died at their homes in Washington and Eisenhower died at the army hospital there.
Yes, US presidents can serve for two terms and many have done it, the most recent being George W. Bush and Bill Clinton.