I have heard that in the history of the United States there has been
two presidential elections that all states didn't vote in.  I would
like to know what years and what states didn't vote.

I count 3 states from various websites, but one in particular has a nice summary:

---
New York did not participate in the 1789 Presidential election.
None of the eleven states that seceded voted in the 1864 Presidential
election. [Alabama, Arkansas, Florida, Georgia, Louisiana,
Mississippi, North Carolina, South Carolina, Tennessee, Texas and
Virginia.]
Virginia, Texas and Mississippi did not vote in the 1868 Presidential election.
---
http://www.jeffwolfe.com/ushistory.html

Oh, and I guess the 2000 election if you count Florida... just kidding!

Thanks for your question.

skermit-ga