You've tried the normal method (delete and re-install) so I normally go for one of those CDs you can buy for cleaning the laser lens. If that doesn't work then as they are so cheap these days I would be looking to swap it out with something like this.
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Do you know that we're all in line for succession to the throne? Really?
Well, if forty-eight million, two hundred thousand, seven hundred and one people died I'd be Queen.