What proof does she have that she purchased the ticket?
Maybe she did, maybe she didn't. People have been known to lie about a lot less than $162 million. Some people play the same numbers over and over, typically a combination that's relevant to them like birthdates or anniversaries. Perhaps she could show that she has played that combination many times in the past. Otherwise, I don't see many alternatives to prove that she ever bought the ticket. Lacking such proof, it'd be hard to say that the money is hers. Of course, she would probably sue and hope for a settlement of some sort.