From what I recall (I wasn't that great of a viewer either), after the town found out about her HIV status, everyone went crazy and her brother got sued for malpractice (since they were practicing medicine together). Linda decides to leave Everwood for good. Andy's sad, but she leaves anyway. I can't remember if she said where she was off to, but she was probably off to see the rest of the world like she did before she came back to Everwood.