What if the popular vote has different results?

Answer 1

The popular vote on a national level does not determine who is elected. Each state is given a certain number of electoral college votes, and the electoral college will normally vote whoever won that states popular vote.
There is no laws saying all electoral college voters have to follow this procedure though. They can go against the popular vote, and chose someone who has not won by majority of votes.

Answer 2

The popular vote has no legal bearing on the national Electoral College Presidential and Vice Presidential elections that occur in December, and its bearing on the November election is only on the state level. Every state is free to decide how it will appoint its electors, and since the 1860s every state's method of choice has been the popular vote, letting the majority of the state's voting public decide. People have been publishing the total national popular votes since the 1820s, but there is no legal reason to do so. Its only value on the national level is that of an interesting statistic. It does of course provide valuable information as to where elections are won and lost by identifying where each Party is strong or weak, and which States are competitive. The most recent example of the popular vote and Electoral College being different was in 2000 when Al Gore won the popular vote but lost the Electoral College and thus George W Bush became President.