how to repair this case?

- Remove the power from the player.

- Get the proper ".upgrade" file as described here.

- Connect the player to your computer's serial port. Do not apply power to the player.

- Double-click on that .upgrade file. If you've got a version of emplode installed, it should begin running the upgrade software. Follow the software's prompts.

- Do not apply power to the player until the upgrade software specifically prompts you to do so.

- When the software tells you to apply power to the player, do it. It should upgrade the player and replace the bad kernel properly.