It is theoreticaly possible, but praticaly speaking it would be near impossible.

To acomplish this, you need to get 51% of the population (who actually vote) to all vote for one person. However, with FPTP, you get one choice on the ballot. Is the average voter going to risk their vote on a 3rd party, or vote for who they belive to be the "lesser evil" of the two that have a shot at winning?

Even if you do manage to get 51%, there's the electoral collage. Never forget, our democracy has built in the ability to overwrite the presidential vote.

Your first hurdle is getting any one to name an independent candidate.

Edit: adjusted some wording to be better.