Harry Potter PC game glitch?

I have the Harry Potter and the Chamber of Secrets computer game and have an annoying glitch that's been keeping me from beating the game. I'd played it nonstop for years, but one day the glitch started to happen. When Harry dies, he does the screaming thing like when he is falling down a pit, but it never stops. I have no choice but to turn off the game. When I restart it, Harry is on a strange glitch invisible platform surrounded by a starry sky. You can run to the edges of it, but cannot ever leave, so I am stuck there and cannot beat the game unless I make it through without dying once, which I don't want to try. Also, it has never been on the debug mode or had anything fancy done to it. Can I fix the game?