All About Scams
You just won 5,000,000 cash.
Obviously there is no money they do it to steal money from the person who is supposed to win the prize. The Internet tells you that you just won 5,000,000 dollars that you don't even remember entering.
Legitimate contest won't make you pay any amount of money to collect your winnings.
There are also such things as need help scams, Often the come in the form of a charitable donation opportunity.
The best way to deal with this situation, is ignoring it. Don't trust anything unless you know the person, there's people who are just trying to get your information to steal money from you.